Every single national champion in the last 10 years has recruited an ESPN Top 10 class the year prior to winning a national championship. So, recent history says that unless you recruit at an elite level then you aren't going to win a title. That does not mean it will always be that way or has to be that way, but it is a very interesting trend.
To break that trend at Nebraska, a place that I don't personally believe can continually haul in Top 10 classes, it will require transcendent coaching. I think Nebraska will also need to haul in a Top 10 class again at some point, or one at least very close to Top 10. Similar to what cm said, I think it will take either elite coaching and great recruiting or elite recruiting with great coaching. I believe the former is more likely at Nebraska.
I also personally believe Nebraska will not return to national prominence until their style of offense reflects their location more accurately. The 500 mile radius rule in Nebraska is not what it's like in the southeast. That means Nebraska should be a run-based team that relies on strong offensive linemen (which we can find plenty of in the Midwest) who then extends its branches into other states to bring in the great skill position players. I don't believe Nebraska can consistently compete at a top level using an offense that favors passing.
We don't need to continually haul in Top 10 classes. We need to get a few good classes, get a conference championship or two, and ride the momentum.
Look. National championships are super rare. I know in the age of Urban and Saban we now think that they're kind of a right or an expected direct variation to money spent on coaches, but that's just not true. We have 5 national championships in 50+ years of relevant football, and we are still one of the more successful schools in that regard.
The goal isn't national championship or bust. The goal is competitive football, with the occasional chances of lightning in a bottle, luck, momentum, or whatever, to hopefully get the chance at one.