It depends upon what class you are thinking about teaching. The program I will start has phd's in their science classes as instructors (physiology, medicinal chem, etc). Otherwise, the other instructors that are CRNAs are either already phd's, dnp/dnap, or are in school now.
You can look at the job postings on the AANA website. It has the most listing for CRNA faculty positions that I know of. It is still a very small list, but it will give you an idea of what the programs are seeking for instructors.