Lol but that's only 2 characters, and Nana is a flashback character with little relevance in the present. Unlike One Piece there are no multitude of characters looking like slighty tweaked version of Ochaco roaming around.
As for duplicates of each other running around, well... Yamato is 12 ft tall. Not a slight tweak. Kinda weird to insist that they can be mistaken for each other.
They're completely different and why are we talking about MHA now lol