My pick would be Shino due to several reasons.

In terms of his abilities, Shino has got the right skillset to deliver presents to billions of homes with his insects. As Shino breeds all kinds of insects with special traits, he is able to carefully select the right kind of bugs to do the job for him. With his high intellect and careful planning, he would be able to deploy durable and speedy insects to reach homes from a faraway place. Chakra is not a concern for him as he is able to absorb chakra with his insects.

Also, insects are hardly ever noticeable at night, particularly in the darkness, so his bugs are able to sneak into homes and carefully place the presents under the Christmas tree without getting caught. Stealth is one of Shino's biggest plus points as he is often being ignored by his mates since childhood .

As far as identifying which kids are naughty and nice are concerned, Shino has got the experience as an Academy teacher to help him with that. Shino is constantly striving to become a better sensei as time passes by and by becoming a teacher, he has developed a better understanding of how kids will act, react, think and behave. His bugs will be able to keep an eye on kids from afar to assess their behavior and well-being. Scouting work is something that his bugs can do and its not easy to detect them.

Story:

One fine day, Shino found an envelop at his doorstep, wondering who it could be from. He opened the envelop and found a letter written by Santa, himself. In the letter, Santa has expressed and explained how difficult it will be for him to deliver his presents to kids this Christmas and needs urgent help from a special individual In his words, Santa described Shino as the type of person who cares for kids, kind-hearted, intelligent, capable and would like Shino to help him with his delivery. Shino hesitated at first as he believed there are more capable people out there who are up for the task. But declining Santa's request would mean a huge disrespect to the man in red, so Shino decided to write back to Santa stating that he will be available on the delivery day. As days leading up to Christmas Eve, Shino has been meticulously planning and selecting insects that has specific attributes that are well-suited for long distance travel and immune to environmental changes. On the night before Christmas, all the preparations are set. The list of naughty and nice kids have been drafted and updated accordingly with the help of Shino's recommendations and suggestions as his bug surveillance played a big role in distinguishing who has been naughty and nice. Under the supervision of Santa, Shino began to assemble his specialized super bugs and *tered them across the region along with the presents. The bugs surround the presents with their body, shielding them, lift them up as a group, and quickly flew to the designated homes in high speed. As the bugs showed up in front of the houses, they began infiltrating the homes and silently placed those presents under a Christmas tree, which gives off a unique scent that only the bugs can recognized. If a Christmas tree cant be located, the presents will be placed on top of the living room table.

Everything is going smoothly until Shino noticed something amiss. He sensed that he has lost contact with some of his bugs which are designated in Konoha. Santa took a notice of Shino's troubled look and asked if something had happened. Shino explained the situation to Santa and Santa called for Shino to get onto his sledge. Santa then tells Shino that he wants to take him back to Konoha to investigate the matter. But Shino felt concerned about Santa's well-being as he already knew that Santa is tired from all of the preparation work leading up to Christmas. Santa gave his reassurance to Shino that as long as he is just making a 1 way trip to Konoha and back to his lair, then he should be fine. After that, Shino got onto Santa's sledge and Santa command his reindeers to sprint to Konoha. When the two of them got there, they took noticed of 5 thugs stealing presents from Shino's bugs. Shino jumped out of the sledge with haste and confronted them. But the 5 thugs bemused him and start assaulting him while Santa stayed by his reindeers to protect them from harm. Shino then uses his Hidden Jutsu-Insect Bog to engulf them in insects and pin them down. One of the thug, the youngest member of the 5, dodged the attack and rushed towards Santa. The young thug sneaked behind Santa, uses his left arm to lock Santa's neck and uses his right hand to point the sharp-end of the poisoned-kunai at Santa's neck. Realizing what had just happened, Shino froze and then asked the young thug,"why are you stealing presents from my bugs". The young thug replied and said its because he never once received a present on Christmas and felt its unfair that everyone else around him got one. Every year, he asked for one from his parents but they didn't give him any. If he cant get presents by asking for one, he'll just have to take it from others by force. At that moment, tears start dripping down his cheeks as he remembers and explains about his past to Shino. Shino didnt say a word and then approached the young thug calmly while dipping his hand into his right pocket. The young thug got startled and warned Shino not to come any closer as he points the poisoned-kunai closer to Santa's neck. Shino then stopped and stood a few centremeters infront of the young thug and pull something out of his right pocket. The young thug noticed there's something in Shino's hand, its a box, as the young thug gazes at it in confusion. "Take it, this is for you," said Shino. Shino paused and continued, "this present is meant for a student of mine who has been causing trouble for others since I met him. I'm hoping to give this to him as he's not in Santa's nice list. But I feel that you need this gift more than him". Then Shino kindly said, "would you kindly accept this little gift from me?". The young thug was shocked by Shino's words and he loosened his grip on Santa and the poisoned-kunai. The young thug looked dejected, released Santa from his left arm, dropped his Kunai and stood aimlessly as he realized his mistake. Shino then leaned in closer to the young thug and gave him a warm hug, telling him that everything will be okay. The young thug then cried while asking for forgiveness from Santa and Shino. Both Santa and Shino accepted his apology and Shino insists the young thug to accept his present. The young thug said, "is it really okay for me to have it?". Shino then gently placed his hand onto the young thug's head and said, "yes, please accept it. Its a gift from me." The young thug accepts the gift as he expressed his mixed feelings of sorrow and happiness towards Shino and Santa. As for the other 4 thugs, they pleaded for forgiveness as they also realized their own wrongdoings. Shino and Santa accepted their apologies and they all return back to their homes. Before the young thug leaves, Shino approached him and said, "come find me if you ever need help with anything" . The young thug nodded and wish Shino well as he returns back home. Shortly after that, Santa realizes that there isn't much time left before sunrise and informs Shino to quickly deliver the presents before its too late. Shino then swiftly summons more of his special bugs to resume the delivery. With just a couple of minutes remained, all of the bugs that were sent all over the region to deliver the presents have returned to Shino in Konoha and all of the presents have successfully been delivered to its rightful owner. Santa applauded Shino and plead for his assistance again next Christmas. Shino accepted his request and Santa then gave him a present for his tireless effort. Its a glowing snowglobe.Shino hesitated to receive it at first but Santa insisted that Shino should accept it. Shino then accepts it and keep it safely in his right pocket. After that, Santa bids Shino farewell and flew back to his lair on his sledge with his trusty reindeers. Shino then walks back home as the sun is about to rise.

The next afternoon, Shino walks into a gift store and have his snowglobe wrapped up as a gift with the intention of giving it to his student. As he walks out of the store, he saw the young thug from a distance, mingling around with his friends in pure happiness. At that moment, Shino smiles as he noticed the bracelet that the young thug is wearing around his wrist is indeed the very present that Shino gave him on that fateful night. Merry Christmas everyone!

In conclusion, despite Shino not being a genius or one of the most powerful ninjas in the naruto universe, he has attributes that makes him one of the most reliable support ninja in a given team. His abilities to control bugs allow him to deliver presents to places that are far away, his experience as a teacher helps him in determining what makes a child nice or naughty, and given by his lack of presence throughout the Naruto animated series, he is more than capable of executing his tasks undetected. Despite not getting enough screen time, he truly is one of the most under-appreciated heroes in the making.