I actually appeared for IE International MBA interview and not MiM, questions of MiM interview might be slightly different than a MBA interview, but they remain same in broader sense.
My interview was around 35 minutes long conducted by a member of admission committee, it was very chill and conversational in nature. There will be questions like- tell me about yourself questions, motivations to apply to this program, why IE, what are your future goals and how will this degree help you achieve them, questions from your resume and essays that you have submitted so be prepared to answer those, how your values align to those of IE, how are you going to manage your finances for the tuition fees, how will you give back to the society etc etc
IE interview style is conversational , they won't grill you , but they would expect to have clarity of thoughts and communication from you.