Ok so now that Sasuke is good again he'll go to Naruto & they'll team up. When they team up, Sasuke's Susanno will mount Naruto's Kurama chakra (Before you say thats not possible, Hear me out. Remember This?
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. Appearently Naruto can give Kurama's chakra to anyone. Whats the stop him from giving it to sasuke? Sasuke's ocular abilities (Uchiha) combined with naruto's chakara (Uzamaki/Senju). When their chakra fuse, Maybe something will trigger a reaction between them. Since they are the last reincarnations of the eldest son & the younger son, their energy reanimates the spirit of the Sage of the six paths & he seals away the juubi inside the shinobi he sees fit to wield the power.