(Tweety, an MPH is a Master's in Public Health

). The combination of an ADN and MPH would be v. strong professionally. I would imagine that you would be hard pressed to find a situation in which you would suffer professionally for not having a BSN. With your existing degree, I wouldn't hesitate to do the ADN (as opposed to a BSN).
Back before there were so many MSN programs in nursing adminstration, the MPH was a v. popular and common degree for nurses who wanted to advance their careers and move into management/administration.
Even if the day did come at some point in the future that you found you wanted/needed a BSN, there are
tons of "RN-to-BSN" programs out there for diploma or ADN grads to complete a BSN that are part-time, on-line, self-paced, etc. and comparatively painless (compared to your basic nursing preparation, certainly!) to complete; they are generally constructed on the presumption that you're working full-time while you're completing the degree.
It's v. hard to give hard, fast advice in these matters because there is so much variation among hospitals/organizations. As soon as someone tells you no, you don't need a BSN, you'll apply for a job someplace that says "MUST have a BSN, we don't care what else ya got, no exceptions, no discussion!" If someone tells you you'll definitely need a BSN, the first place you apply for a job will say, "Oooooh, an MPH!!! Sign here!!"
Best wishes for your journey, and welcome to nursing!
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