OMAC
This isn't some new "nano-infected human turned superhuman killer" OMAC - this the the real deal, baby.
Created by Jack Kirby in 1974, OMAC was a sci-fi story set in the future. Buddy Blank, a general loser of a guy, is chosen by a giant computer in orbit named Brother Eye to become the One Man Army Corps! The stories dealt with OMAC fighting the threats that Kirby foresaw in the future - class divisions, genetic manipulation, virtual reality, dictators threatening the world, and killer robots.