Rather than judging your decision, I will list down some merits of both colleges and leave the rest for you to choose from.

Reasons why one should choose IIM Kashipur over NMIMS:

• Smaller Batch-size: IIM Kashipur has a relatively smaller batch size than NMIMS. This means the placement opportunities will be better and attention given to each student will be more.

• Lower fees: Mumbai fees are around 21 lakhs for two years. Also, it does not include the accommodation and food expenses that a person will have in the two years. The minimum expenses in a city like Mumbai will stand at 20000. The total fee is much higher than IIM Kashipur ( INR 1730000).

• Specializes in Operations: The leading domain of IIM Kashipur is operations whereas NMIMS has limited scope for the same.

Reasons why one should join NMIMS:

• Better opportunities in terms of companies, packages, and roles than any other new IIM 
• Better location than the new IIMs
• Strong alumni base

So if you are confident that you can remain among the top 200 go for NMIMS, else IIM Kashipur it is.