Lets be realistic: a healthy Nagato is virtually undefeatable. He may need a few of the paths out, for different fields of vision to cover all blindspots, but Nagato himself will use the power of a few paths. He can absorb ALL chakra, bring back the dead etc. Naruto beat him because he was half dead from destroying the strongest village, fighting a few hundred shinobi, and because Naruto had a good amount of info on him.
However, Hashirama could use Bringer of Darkness and pwn the boy. Rinnegan, like any eye is vulnerable to genjutsu, and Bringer of Darkness is clearly one of the best out there. Also, Hashirama's flowers can put them all to sleep. It will definitely be a very explosive fight. If it comes down to outlasting the opponent, Hashirama wins. Also, Hashirama can just call out the 7 tailed beasts he controlled at one point and completely own Nagato. 7 Bijuu balls at different targets cant all be absorbed.....and the distraction to all bodies would leave an opening. Ill give it to Hashirama, even with no restrictions for Nagato, as Hashirama is just on a whole another level to almost all shinobi, except SO6P, Edo Madara, possibly Tobi/Hiruzen