Yeah, but we already got through Zero, same as X except not as strong and he has a sword.
And Megaman is definetly thought of as a good match but he doesn't have that many votes since most sided with Samus. Megaman sounds like he'd be the second biggest voted though. Specially X and Trigger.
As for Nitros, I suppose you do have a point there. Only bomb that'd be good is the Black Bomb from near the end of 64 The Second Attack gotten from Bulzeeb. Of course, we aren't allowing specific toward the battle, just their most recognizable and trademark stuff so he'd be stuck with his weakest attack Fire Bomb. Nitros, he DOES have most of that stuff for his most recognizable equipment, but that arena of his wouldn't be loaded to the brim with traps and stuff so Crono wouldn't have any problems destroying barriers and getting to Nitros.
I'm pretty sure I know what you'll all say but Issac from Dead Space? Lightning fast reflexes(gotta have them to get through that Space Station), takes on some pretty over the top characters, and certainly when it comes to close range combat although he's just human he has excellent skills close range(considering it's how you do the majority of the killing in the game limb from limb). Think he could survive against crono long enough to put up a challenge?(and this isn't including Luminaire, that's dead obvious it's results)