Nom is a mutant that hales from the Days of Future Past. He fought alongside Bishop and the others of his reality in the Xavier's Security Enforcers team. He is taller than 7', he is covered with (if not made of) solid rock, possesses limited control of geological objects in his vicinity, and is practically invinceable against physical attacks. When Bishop seemingly died after a particularly ferocious battle, Nom held him in his arms as he "passed."
It is unknown if he retained his rock form and powers post M-Day, but it is assumed he was among the 98% of mutants to lose their abilities, since Beast did not mention him (like he did others from the same reality) as having survived the catastrophe.