If I had a nickel for everytime there was a popular robot character who first game in the US was on the NES in 1987, and have the word man in their name I'll have 2 nickels. Yea bomberman is older since he techincally got his start in 1983 in Japan, but we're only talking about the US here.

Models sources
Bomberman -ThatOnePaperArtist
Classic Mega man -Shynnobi