1) Scott Frost
Obviously he would be the ideal target. Being from Nebraska and part of that program, he would no doubt give it his all and he'd be able to sell recruits on his own story. But it's not a slam dunk that he would go there. He could have several other good options at the end of the season.
2) Greg Schiano
Here is a name that hasn't gotten enough buzz in my opinion. I mean, the dude won at Rutgers. His intense style wore thin in the NFL, but would be great at a place like Nebraska that has lacked physicality for quite awhile.
3) Chip Kelly
Say what you want about fit, but he took Oregon to the next level and they couldn't sustain it once he left. The guy is a really good college football coach. If you are looking for a college football coach and he says yes to you, you say yes to him. With that said, I think he ends up at UCLA.
4) Mark Stoops
There is another Stoops brother out there that should become a hot candidate for a big job. Kentucky has gotten progressively better each year he has been there. His teams on offense have been physical and have been run first. He's about to hit his head on the ceiling at Kentucky and it might be a good time for him to move on.
5) Matt Campbell
He's done a nice job in the short time he's been at Iowa State. My only concern would be that he's been in Ames for less than two years so far. He'd be higher on the list if he had another year of leading Iowa State to respectability under his belt.
6) Kevin Wilson
Indiana is relevant because of the work of Kevin Wilson. It'll be interesting to see how long they stay that way now that he's gone.
7) Bret Bielema
He is arguably the one that took Wisconsin to the next level after the Barry Alverez era. He's lower on the list though because although it's clear he can build on a foundation that was already built, it's unclear if he can build a foundation of his own.
8a) Dave Aranda
He's been a nominee for top assistant coach on multiple occasions. A young guy that could maybe bring some life into the Cornhuskers defense. He's been in the midwest and been down south so he might have some solid recruiting ties.
8b) Brett Venables
He hasn't coached in the Big 10, but he has a resume similar to Aranda. Been nominated as a top assistant multiple times and has been well traveled. He played college ball under Bill Snyder and has coached under Bob Stoops and Dabo Swinney which gives him a pretty good pedigree.