Brock, 3rd round katagatame.
Gustafsson, TKO rnd 2
Nam Phan, Decision
Ross Pearson, Decision
Njokuani, KO rnd 2
Stun Gun, decision
Won't even bother picking between Riddle and Ramos, LOL.
Diego Nunes, submission round3.
The reason I'm picking Brock: This is MMA not K1. And while winning K1 is impressive, guys like Badr Hari don't succeed in MMA for a reason. It's a different sport. So, yes, if the fight stays standing, Overeem takes it. But I don't think Brock is that stupid. The fight goes to the ground. You don't combat a lifetime of wrestling with some supplementary wrestling and training a sprawl for a few weeks. On top of this, in MMA, the only noteworthy opponent that Overeem has beaten since 2006 is Werdum...and that was a shitty performance. It also showed that Reem's gas tank is questionable.
That being said, Brock holds him down in round 1. Depletes his gas tank. Overeem will be too tired to use speed and his power will be a bit more sapped. Round 2, Brock wears him down adding heavy punches to the mix. Round 3, Reem is exausted. Brock takes him to the ground with ease. Mount. Punches. Katagatame.
The only thing that changes this prediction is if Overeem lands one good shot. I just don't think he'll be able to land it.
Reason for Cerrone: He's just more skilled than Nate, but Nate's never been KO/TKO'd. Cerrone beats him nicely, but takes it the distance.