IMO it could be a draw because Choji's expansions, while making his hits much harder to avoid, also make it much easier for Kankuro to land a hit on him. Kankuro usually has 1 or 2 puppets kept in secret, and a main one for combat. If one of those hidden ones have a poisoned weapon, than Choji would probably get hit since he lacks the proper reflexes to defend against small yet deadly attacks while in his larger form. He's the type that tanks big strong attacks instead.