Dear student,

Let me tell you that, IIT's don't offer BSc courses. Some IIT's offer integrated MSc course. And with the JEE Mains score, you can't get IITs. You will only get NIT's with JEE Mains score. To pursue any course from IIT's, you have to give JEE Advance exam. And with this score you will get admission into B.Tech courses at IIT's.

Hope this helps.