Yeah, the more I see about Nolen, the more I like him with the 12th pick. Some have him rated lower than that, but others seem to have him rising. He's a strong run stopper with pass rushing ability. May need to develop some as a pass rusher, but the skills are already there.
Mazi is already better than Trysten Hill and this defensive scheme should allow him to build on what Zimmer was having him do. Nolen would be give us a DT who can rotate in for either Mazi or Odig. (I'd actually play him next to Mazi on early downs.)
I'm hopefully we go hard after DTs in this draft (two in the first three picks) instead of bringing in journeymen or players at the end of their career. Maybe Mazi never gets there, but maybe he can be part of a rotation with other quality linemen. Same with Odig in a way. I don't think he's the stud 3-tech you need in this defensive alignment, but he is a very solid rotational piece. Nolen could be that stud.
The other DT I really like is Derrick Harmon, but his value seems to be a little lower still.