I don't see CMS leaving for anything short of a quality, decent-performing blue blood, and that is not today's Nebraska cornhuskers.
I think CMS is loyal to UK....as much as a HC can be in CFB.
Even if he were "willing to listen" --
I think his slow turnaround at UK is a turnoff to "big-time" programs who expect a nearly immediate return to winning. They will not give him (or anyone) 3+ years to create a OL/DL-centric program that takes multiple recruiting classes with retention & development to create the talent/depth to win in Stoops' fashion.
I also think our offense is still considered to be conservative when compared to UT (Chumley), USC (Riley), Kiffin (baker's dozen of hires/fires), Wake Forest's HC (whoever he is?), UTEX (Sark), etc. I suspect Blueblood-U will be looking for high-flying 40+ PPG in a new coach and not run-first/pass-second model for which Stoops is known.
I believe Stoops is safely at UK (for now) and certainly not going to consider seriously a NU offer beyond bumping his own personal and staff pay a little bit as is par for the course.
GBB!