Well there are a lot of shinobi that can counter/destroy celestial terra blast.. First of all we can only assume that it will stop absorbing at some point, or at least it should become weaker over time, as it absorbs more.
So Obito will have no problem with it. Same goes for Minato or anyone else who have a S/T jutsu to escape. Now this doesn't mean they beat him. If Obito has his rinnengan as well, though this scenario is impossible, but lets just say he has.. Then he can summon gedo mazo to fight the 6 paths, and it is likely to assume it could resist the celestial terra blast? It seems pretty durable. But can't know.. However, if Obito figured Nagatos secret, he could possibly track him down? At least Tobi could, but then it'd be 2v1 I suppose ^^
Deidara could also destroy it U_U I think he has better destruction power than a tailed beast. He is also the most efficient member of akatsuki at capturing beasts.. Deidara could also kill Pain including nagato. We saw the size of his self-destruction. It would even reach the real Nagato, and I don't really see how he escapes that. No need to find it in the manga really, all should remember the size of self-destruct.
Danzo could also survive celestial terra blast. He got mass izanagi, and he is pretty experienced after all. We know that KA can go through even an edo body to the "user", so it is likely to believe it would work on the rinnengan in the same way. Now I don't have proof, so I wont really try to prove Danzo beating Nagato + Pain - it all depends on the KA.
The celestial terra blast starts off being pretty "small". So it is possible Kakashi could transfer it or transfer some of it to another dimension, thus he could escape it, but he couldn't beat the 6 paths anyway, so pointless mentioning more..
Since Hashirama beat Madara with perfect susano and Kurama, it is likely to believe he could beat Nagato as well. Though the evidence of him beating Madara is the only supportive "evidence" from the manga, so can't really say this either.
Naruto on the other hand. I will give this one to him. Am too busy to look in the manga, but he has become pretty decent lately. His tbb is at the level of 4 tailed beasts. He has SM bunshin at the same time to protect him. He could simply make a bunshin of Kurama mode and use the bunshin to destroy it. I mean he also had SM bunshin at same time when he destroyed those 4 tbb, so he can do it even when he divides his chakra. His speed is insane, so he will not be caught by the other nagatos easy. He still has vast amount of summonings to help out. Sensory type. Kurama can make several arms to guard against any pain in range for anything..
So my deduction is that only Deidara and Naruto can be proven capable of defeating Pain in an even battle, where god realm doesn't need to wait before acquiring his powers. Deidara, however, would tie it, since he will die as well. However, if Obito has his paths as well, he will most likely also be able to do it, or at least put up quite an even match since they are edo tenseis.
Of course Madara might be able to smash it with his giant rock, but I suppose he is a pretty obvious winner, everybody knows U_U