I really don't like the idea of going after Frost.
First, Chip Kelly is an innovator. Always was. He was when he was at New Hampshire, he ran an outstanding offense at Oregon, Bill Belichick's consulted him on how to run an offense, and now he's been hired by a NFL team to bring his acumen to the pros.
The current Oregon HC was brought up under Kelly as an OC and Frost was just the WRs coach before that. Frost is in his first year as an OC. If Oregon, in year #1 of post-Kelly, is doing well, then Kelly has successfully bequeathed his system to the school. Not to take away from Helfrich (or Frost, who is a name OC under a HC/OC, no?).
Even with more successful years at Oregon, Frost will not be a superstar OC. Although he may have a good reputation and great job prospects, his status will be completely different from Kelly the ace offense guy or Bo Pelini the defensive mastermind. So if we bring Frost in as a head coach, we're not going for a star coordinator. Which is fine; we're looking for a head coach after all. What are his traits as a HC? Maybe he totally gets it. Maybe he knows how to assemble a team of assistants, lead a team of young men, and face the media. Maybe he's the whole package, or maybe he's not. How can that be anything but totally unknown? It's a hell of a gamble.
In my opinion, that's a gamble for a small school to take, and not a major program like Nebraska, especially coming off the heels of a disaster (which is what it would take for Bo to be gone) that needs repairing. If it ever doesn't work out for Bo, I'd want a guy who has proven all of those successful HC traits at a lower level and give him a shot to do it in the big leagues.