No, that's not right, the Big 12 can fill it's bowls with 6-6 teams even with 7-5 teams not invited, unless you find a source that says this changed from last year.
http://www2.ncaa.org/portal/media_and_even..._6and6rule.html
Look, it seems like a reach for the Huskers to win the last 2, but KSU lost to IOWA STATE and Colorado got blown out by Missouri at home worse that Mizzou beat us in Columbia. Nebraska isn't the only team with problems.
IF Nebraska wins these two, there's a very real chance that KSU, CU, Okie State, and A&M also finish 6-6. Check out their schedules. 4 of those 5 teams will get into bowls. In this scenario, unlikely as it is, Nebraska will be the only "hot" team of the bunch.
If you want the season to just end, consider this extension to the scenario:
Osborne fires Callahan after the CU game, even with a win. Gill or Pelini is quickly named and in place for the bowl game. Two game winning streak, new coach...you think this might be interesting?
I'd prefer this over a 4-8 season.