Nebulim is a fighter who focuses on pure defense while Genos goes 100% in on attack power. So their fighting styles really contrast with each other and that would make for a good fight. At the end of the day what this comes down to is the fact that Genos would be able to punch through Nebulim’s defenses. With defense out of the way there is no path for Nebulim to be able to stand up to Genos’ speed and strength for very long. Genos wins.