As with everything, it depends on the NP. There are a lot of NPs that I would prefer managing interns/medical students over certain MDs who it would otherwise fall on.
On average, your NPs are going to know a crap ton more than a new clinical medical student. Whether they went to medical school or not is largely irrelevant. Good preceptors/teachers are good preceptors/teachers. Especially when you talk about stepping into the clinical teaching realm, things are not as cut and dry as the last couple letters after your name.
Should NPs be doing an MD's job? No. But, I don't think medical education is solely an "MD's job". I had PhDs, PharmDs, nutritionists, MDs, DOs, PAs etc teaching me as a medical student. I learned more about how to be a good resident my intern year from our service NP than I did from any of our faculty. Did I learn any surgery from her? No. Did I learn any book knowledge? Not really, maybe a little. But, how to function in a clinical setting, even as a relatively advanced intern? Nobody was better.
Likewise, when I was an MS4 on an away rotation, there was a PA that essentially ran the minute to minute management in the SICU. I would rather have him teaching medical students than any faculty that was around for certain things. Managing every last bit of education, probably not. But, certain had a role to play.
I don't think precepting a single clerkship if it was FM/IM/etc. is that crazy or bad just on virtue of them being an NP.