Chouji would be in a bad situation if he fought Sasuke. I don't know if he is fast enough to hit Sasuke, but I know supersizing himself would make him an extremely easy target for Amaterasu, the flames would soon spread and kill him. By the way, dodging Amaterasu is not as simple as fly, you need to be an exceptional speedster to avoid it.
An how do you expect Chouji to hit Sasuke if he is not looking into him? Will he blindly punch the ground at random and hope to land a hit?