Hi, It depends upon where you want to teach and whether conducting original research is important to you. A university job will require a doctorate with an active research component, whereas a job with a college will only require the MSN and be focused on teaching, rather than research. In terms of selecting a specialty, you likely can do this. Many educator job announcements will look for specialization in med/surg, OB/Peds, Psych, etc. The key is to not limit yourself too much to one specialty, because they'll also want someone who is strong enough in another area to step in and teach a class if needed. Good luck!