If you have completed your Bachelors in Nursing from Bangalore and want to do MPH, then at first you need to have your foreign degree evaluated by your-choice-of-university-asked evaluation organization. Many university will take evaluation done by any members of NACES (list is here: http://www.naces.org/members.html). Some university will specifically ask for World Education Services (WES), and other will do the evaluation themselves. So, when you apply, look up the university policy for foreign students.

All university will have their own specific prerequisites for MPH. Once you have your documents evaluated, you will see if you have to take any courses in Bachelors or can directly apply for MPH. Anyway, there are too many variables here. So, unless you figure out which university you want to go, there is vaguely what you have to do. Based on my experience, I have seen a couple of MPH completed friends (Nepali, and non-Nepali) who are unemployed. Therefore, I would say do more research. MSN might be better for you if you have completed BSN already.