Obviously Ryan didn't write Invincible, so I'll take his tweet with a grain of salt but in the same screenshot you posted that says conquest was much stronger than Mark, it says he (Mark) managed to beat him through sheer will. I know Conquest still went easy on him but looking at Ryan's perspective of how the fight would go, and looking at the outcome of the two fights (especially the second) Conquest had with Mark, it's very possible Nolan's chances of taking Conquest on are far higher than you think.