Nursing license

It would be a HIPAA violation. It depends where you misplaced them and who found them I imagine. I don't think any of us can definitively say what your BON will or won't do if you get reported

It actually most likely is not a HIPAA violation. HIPAA applies to covered entities, which the school likely is not - and if they are, the health records they maintain are part of an education record and therefore subject to FERPA regulations instead. Not too familiar with FERPA so I'm guessing it's no more lenient, regardless.

Do you have a good relationship with any of these people?

Could this be a matter of misunderstanding (i.e. they think they are required to report you personally to your BON)?

Was this an egregious sort of incident or why are they so freaked out?

If there's anyone you have a very good relationship with, I would consider asking them what is driving the belief that they should consider reporting you. I would consider putting a bug in their ear, so-to-speak, that reporting to BONs for such things is unusual; it's certainly not customary or "the law." If your disclosure is indeed subject to FERPA, how have they handled other accidental disclosures (such as on the part of teachers, secretaries, etc.)? Are those people punished similarly? This doesn't become "HIPAA" just because you are a nurse. And it doesn't need to be reported to any BON.

This is assuming that you haven't purposely disseminated someone's protected information.

It might be safest to just get a lawyer familiar with the issues and let them "talk this through" with your employer.