My sister is a CNA in Oklahoma and she has a felony that was not expunged, so you shouldn't have any problems. The only issue that she has is that she is forced to work in nursing homes because hospitals have strict background checks. I don't know if it would prevent you from getting a RN license, though. Hope that helps!
It depends on which type of expungement you have. There are at least two types. Title 22 O.S. 991c and Title 22 O.S. 18 and 19. The second one is the stronger one. Please read the statutes and/or consult an attorney. Under Title 22 Section 19 you can find the following lines regarding the procedure:
"D. Upon the entry of an order to seal the records, or any part thereof, the subject official actions shall be deemed never to have occurred, and the person in interest and all criminal justice agencies may properly reply, upon any inquiry in the matter, that no such action ever occurred and that no such record exists with respect to such person."