i say nagato because if sasuke uses one of his jutsu's pain absorb's or repels it. sasuke has no info on nagato and couldn't have known that there even was a "nagato" all he sees are 6 people with the rinnegan. he would have a tough time fighting a body of pain one on one because their eyes are linked(naruto could defeat a body of pain because of the bigger range of sage mode). i guess pain can absorb amaterasu because it is a justu and if he can't than he just repels it back to sasuke's face
if sasuke does manages to take out one body they change formation and one of the path's that revives(forgot his name) just revives that destroyed body and their back and running
if sasuke would find the real nagato in a way that i don't know they would hold him back from the place were nagato controlls them, and if sasuke would discover the location and meets nagato. nagato would just control him with his chakra and shoot a spike at him like he did to naruto. i don't think sasuke can repel nagato's control with his chakra like naruto did eh.
so in the end i think nagato would come out as a victor
sorry for the spelling xd
if sasuke does manages to take out one body they change formation and one of the path's that revives(forgot his name) just revives that destroyed body and their back and running
if sasuke would find the real nagato in a way that i don't know they would hold him back from the place were nagato controlls them, and if sasuke would discover the location and meets nagato. nagato would just control him with his chakra and shoot a spike at him like he did to naruto. i don't think sasuke can repel nagato's control with his chakra like naruto did eh.
so in the end i think nagato would come out as a victor
sorry for the spelling xd