Nnadi, a 6-foot-1, 299-pounder from Virginia Beach (Va.) Ocean Lakes who's rated second at defensive tackle by Rivals.com, is already all business.
Rated No. 34 overall, Nnadi has been preparing for the Five-Star Challenge for months and he's ready to go.
"A lot of these linemen have a lot of talent," Nnadi said. "There is a lot of competition in the country. You know you have to bring it all out.
"I've been working hard for this. If I'm not the MVP, at least make me a five-star. That's what I've been working all offseason. If I'm not No. 1, that's fine with me but I know I'm a good football player.
"If I do as well as I hope to do, there will be a lot of eyes on me. If I don't, I'm going to be right in the trash can."
Nnadi is taking this seriously. Andrew Brown was taking a different approach.
The top-rated defensive tackle and seventh-best player by Rivals.com was loose during registration day, but that should change Saturday morning. Brown was at the Five-Star Challenge last year, too, so he knows what's going on.
Brown knows if he's not ready, he could get exposed.
"It's fun," Brown said. "I'm just here to have fun and compete. I'm just feeling good. I'm feeling really good right now."
It's expected he'll be a little more focused at Soldier Field.