Rasengan at base=decent sized explosion, size of a boulder, as powerful as Chidori, around small town level. Chidori at base = penetrates through boulders with ease and penetrated Orochimaru (on par with Rasengan), small town level.
Now scale these two to TBB and PS Chidori and they've gone from small town level to island level. That's some insane power-up.
Now go back to base Chidori and scale it to city level since it destroyed the meteor with utmost ease and still caused a huge explosion. Add it to PS and it scales massively once again, possibly country level. Don't see why he can't surpass Indra's arrow when one looks at it that way imo.