Naruto Sage Mode - That was when he trained to combine Rasengan and Wind Chakra. That's how he got Rasen-shuriken. That's entirely different to Six path's Rasengan. Where he doesn't combine it with anything like normal Rasengan, just in Six Path mode.

Rasengan is basically a template to fuse with other Chakra Nature, as he has shown in Manga (and Anime), where he fused it with Magnet and Lava.

Therefore Rasengan was never Wind attribute to begin with.

Why it's Nin only, not Nin Tai. - Dunno.

To classify Tai, I thought it has to be physically involved, but Tendo's mystery is Nin Tai, but no physical contact.

According to the Wiki, it Wind. Even if it not, does it really matter? In terms of game-play, I rather choose attacks with with no attribute on the safe side due to stacking of nature resistances.

As far as I know, all rasengan are in the form lf wind (Minato, Jiraiya, Naruto, Konohamaru, etc...), but then Naruto use variation, like in the tailed beast rasengan, where he fuses another chakra like Lava Rasengan (Roshi's/Son's Lava Chakra), and another variations.

Wind Release: Rasengan and Rasengan, they are different though.

According to wiki "The Rasengan is a spinning ball of chakra formed and held in the palm of the user's hand" ...

It's just chakra.

Thus there are so many Reddits about it too. It's just chakra with Wind Release, you add chakra nature.

I was referring to the exact name "six paths: ultra big ball rasenshriken" which what in-game naruto 6p's mystery has when i searched it on the naruto wiki. I know that rasengan by itself has no charka nature but for this jutsu it is apparently wind.

Well as the name implies, it's a rasenshuriken so it should technically also have the wind attribute since a rasenshuriken is made up of a rasengan mixed with wind element. Basically, 6 paths naruto's mystery is two really huge rasenshurikens that utilizes six paths chakra, nine tails chakra, and nature energy.

If it has wind in it, then it should have it in the game as well, its simple xD

I mean, the sixpath rasengan is a rasenshuriken, and the ''sage naruto'' has a rasenshuriken mystery that has wind element, so why does six path shouldnt have it too?