see this msc in nutrition and mba two are totally different line. i know that many of people are now rushing to join mba colleges to get high salary job. please remember if you do a work sincerely you can rise from any department of study. mba has different courses like mba in finance, hr management, marketing etc. some one from commerce line background has some advantages . msc in nutrition has also demanding job , many government and private medical , food processing company hires candidates.
so the decision is yours.