While Naruto is heavily favored to win, Neji could probably still use 8 trigrams 64 palms to shut down his chakra pathway since senjutsu chakra is not sentient in itself and most likely wouldn't be able to open his tenketsu. Their taijustsu would be pretty much equal on these terms. The vacuum palm is likely on equal terms with naruto's invisible punch as they are both invisible and powerful strikes. The biggest thing Naruto has is the rasenshuriken, though he would have to be a considerable distance away from it to use it against neji, so chou odama rasengan would probably be a better choice for him to use in close range.
This explanation is just showing that there is a possibility that Neji might win, even if it is slim, with his gentle fist techniques.