Nog by TKO in the 3rd
(settle down everybody!)
I think even gassed, Mir will see all of Nog's sub attempts coming. So I think Nog will have to mount and finish it with strikes. I realize this is a rare thing for him but he also rarely fights a guy with Mir's level of BJJ.
I think this will go like the Werdum fight except that Mir will gas early enabling Nog to mount and rain down strikes.