The Reason why nagato couldn't make chibaku tensei so big because he is an uzumaki and a true uchiha can make it big.
And that's why SO6P was able to do it into size of a moon in his deathbed.
Here is a picture of nagatos chibaku tensei
And heres SO6P's Chibaku Tensei
So we have seen naruto in his toad sage mode beating six paths of pain , and also jiraiya vs six paths of pain but kabuto dragon sage mode is fighting against sasuke and itachi (2 susano'o) and doing well :D
So which one do you think is Better ?
I'm soo sick of this sharingan thing it only keeps getting better and better but we haven't seen the rinnegan getting better But we know Rinnegan>Sharingan:scorps: