Most programs require that you have at least a Master's, although some community colleges till use BSN-prepared people, esp. as clinical instructors. Many BSN programs prefer doctorally-prepared people, but often have a mix of Master's- and doctorally-prepared faculty.
It doesn't have to be an MSN in education; schools
try to have nursing faculty with a wide variety of clinical backgrounds -- advanced practice, management, informatics, etc -- and they often specifically want faculty with an advanced degree, certification and extensive clinical experience in the specific area they will be teaching. Actually, over the years I've been in and out of nursing education, I've run into only a few people who did
have an MSN in nursing education -- most have a clinical/practice degree.
My advice (for what it's worth
) would be to take the time to figure out what you really want to do before getting into a grad program -- don't just do it for the sake of doing it, and don't just get into whatever program is easiest or most convenient. Whatever graduate degree you pursue, you're going to put a lot of time, blood, sweat, tears, and $$$ into getting it -- it might as well be something that you really want