-from the manga we know that Nagato is a descendant of Rikudo , and he is the best at using the Rinnengan beside Madara. So he is better at using the Rinnengan than Obito. As proof : Obito needed kabuto to make his 6 paths of pain , which is Nagato's technique.
-with all the techniques that Nagato has, they are useless against Obito except the one that takes your soul away with a touch. So the winner will the one who touches the other first .
-Nagato is a sensor type (probably the best we've seen so far). He was able to predict MS abilities before they where launched and he was the only person who could pinpoint Kabuto despite him having a barrier that was effective against Zetsu and Obito. So Obito's surprise attacks will not be effective against Nagato. Nagato will be able to predict his kamui.
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-Nagato was considered a strategic genius by Jiraiya , he mastered all nature type transformation and he also mastered Yin–Yang Release which was never done before. Obito will not outsmart Nagato.
-Speed feat: Obito(he wasn't as fast as the 4rth) went toe to toe with Minato. A crippled Nagato was fighting BM Naruto and Bee(he almost killed them both). I consider them equal in terms of speed.
-Decisive feat: At the end of manga 364 the author stated that Pain was the strongest member of Akatsuki. At that time Tobi aka Obito was part of Akatsuki and he revealed himself as Madara.
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Conclusion: The winner is Nagato....Sorry for my bad English

...this is my first post

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