Which B-school should I choose? I have converted NMIMS Mumbai and secured the seat for name sake but have no intentions of joining. Other options are IMT Ghaziabad, IMI Delhi and all baby IIMs.

It is subjective and it completely depends on your goals and your preferences, and how much tag matters to you.

It's ultimately your call to take but here is a list of a few parameters you can/should look at:

1. Return on investment (RoI)
2. Reputation of the Institute
3. Courses Offered
4. Alumni Network
5. Long-term Benefits

Totally my opinion though - Go for IIMs.