One of my friends appeared in the NMIMS interview a few years back. Here is his experience in brief. 

• His case study topic was related to the competition between Patanjali and Hindustan United Ltd. 5 mins was given for reading the topic and 15 mins were given for discussion. After 12 mins of discussion, the students were informed that they had only 3 mins left. The group consisted of 12 students and there was 3 panelist. Every student had assigned chair numbers for case discussion and no changes were made in sitting arrangements afterward. 
• Within 5 mins of completing the case study, he was informed to prepare for the personal interview. The interview duration was 20-25 mins. The interview was taken by 3 panelists. First, he was asked to talk about himself for a bit. There were questions regarding his SOP, his academics, his interests, and Economics. They also asked why he wanted to pursue MBA and join NMIMS.