I think Nagato is about to die. Naruto has the uncanny ability to make people see their error/ or following the wrong path. To begin with Nagato is aiming for peace, although taking the violent path.
So Naruto will more or less defeat GOD pain and reach Nagato.
Nagato is no condition to fight Naruto. Naruto can kill him with a RasenShuriken. But thats highly unlikely. I think Naruto will instead change Nagato's ideals and make him the road to peace is not through violence and pain. I think before he dies, as he is in a such a weak condition, he gives Naruto a gift for him to defend himself from Madara Uchiha.
I personally think if Nagato gives him one or two of his abilities then he might be able to match Madara Uchiha someways.
Naruto is powerful and i know that and Itachi gave him a gift but i think there has to be a Rinnegan sucessor. I believe Naruto needs it becaue of few reasons:
-Naruto won't be the container of demon fox, so he will lose a lot power later on since for something big to happen, demon fox has to be removed from Naruto with the rest captured, except for killer bee. But what would be the point be of capturing the rest if Naruto in the end is not?
-He can't utilise SAGE MODE because of demon fox but the problem is Pa frog is most likely dead. So he can't undergo the fusion thing. But i can guess he will master it someways, but there is a time limit to it. And with people like Madara, you can't possibly do it with a time limit.
-Itachi's gift is most likely a one off and also for Sasuke. After its used it would go.
-Also if Naruto was to gain Rinnegan would then be able to match Sasuke with MS. Also Sasuke indicated he has a very powerful one at that or a secrete Jutsu. How in the hell is he going to keep on matching Sasuke if Itachi's gift is gone after inital use.
-Also my strongest point is NAGATO himself wanted peace through any method possible, but now dying and no sucessor since Rinnegan would dissapear from the world, Nagato gives Naruto the: Rinnegan
. Like Itachi sees Naruto to be loyal Sasuke friend, who wouldn't kill him, Nagato might see Naruto as a future for peace.
I know its just a silly assumption but a lot of thing in the future could go against him big time. I have the feeling Nagato is not all that bad in the inside as Madara Uchiha.
Also if Nagato was to give Rinnegan and makes Konan see Naruto as a path of peace, then she might help Naruto after Nagato dies.
Also I like the idea of Nagato training Naruto, or so before he dies. Thats way he would indeed be on another level. Also Kakashi is most likely dead and with the rest who would actually train him.
Wishful thinking but anything could happen.
Nagato could be bad we assume or Nagato being lost in revenge/anger/suffereing but good in the inside. It could be Madara Uchiha doing?