What is advisable, to join the PGDMM/PGDPM at NITIE or get a job?

It's a subjective question and mostly depends on your profile. PGDMM would be advantageous, if you are a fresher, especially with a mechanical or manufacturing background. It is better in terms of securing a good profile, a good package (Avg. 12 LPA), and robust manufacturing domain command.

A few years of work experience would be preferable for the PGDPM course, but it is not required. It's a safe option to play for both freshmen and those with a little experience because it improves your profile, package, and adds the rich experience of a top MBA school - NITIE.