So nagatos power is madara power

[Zavage10]

It is quite clear that the eyes that nagato had came from madara. Madara has shown more power with eyes, yet nagato has shown more techniques does this mean that nagato has better mastery or that madara has chosen not to use the full set yet.

 

[The Hidden Shinobi]

We need to remember how long madara had the rinnegan for and how long nagato had the rinnegan for.

Of course nagato has more mastery with the rinnegan it was implanted in him at a very young age. Also because it was implanted nagato has to purely rely on the rinnegan where as madara unlocked his rinnegan the correct way progressing from the sharingan so madara can reply on his sharingan as well.

With that said you need to remember how long they both had the rinnegan for.

 

[Invsblphntm]

Its been hinted, it's not a fact. Yes, Nagato had better mastery he lived his entire life with them, Madara got them just before his death.