This team is better than u imagine

this team actually have 8 combo,can even 9

try the same BT

the most important BT on choji is mystery and chase

Shikamaru most important BT is both chase

fire man

This is ok, but I doesn't get Choji to his full potential. For that, he needs to be healing on pretty much every attack he does to activate his scaling. So you need a character on the team with him that provides leech. The two typical combos are Choji and Guy or Choji and Lightning main with ANBU tactics. So here are two options:

It's also important to note that Fire main can provide leech, but only for when ninjas do ninjutsu damage. Choji's standard is taijutsu, so with only Fire main's ninjutsu urge passive he still won't scale outside of using his mystery. That's why Guy or Lightning main are better, because all of Choji's attacking skills are either pure Taijutsu or both Tai and Nin.