Certificate

Yes,
TNOU provide a Certificate programme in food and nutrition via correspondence. Please refer to the link provided below for further details regarding this course, admission process, eligibility etc.
https://www.shiksha.com/medicine-health-sciences/dietics-nutrition/course/certificate-program-in-food-and-nutrition-tamil-nadu-open-university-anna-salai-chennai-113398

Hi Shashank,
MBA salaries in India depend greatly on the business school, its reputation, academic performance, qualities, prior work experience, company, location, tie-ups with companies, etc. Graduates from top B-Schools get an average starting salary of Rs.15 to Rs.20 LPA. Otherwise, you can expect Rs. 1 to Rs. 3 LPA.

Most probably, no. because, for NET eligibility, you need to have a degree approved by UGC or in some cases AICTE. Since PGPM is a certificate-based management programme it can't be used as a medium for getting into NET. But if you have opted for the MBA degree which is offered as an option from ICFAI Dehradun and which goes parallelly with your PGPM programme then, in that case, you will be eligible for NET as MBA degree by ICFAU university Dehradun is UGC recognised.

You will get a job, if you have ability and there is no course, which can give 100% job guarantee.

No, you are only eligible after you clear your intermediate, i.e. class 12th.