You can check your chances in various colleges based on your score and category, you should try Careers360 college predictor and rank predictor.

Link for Careers360 rank predictor:- https://engineering.careers360.com/gate-college-predictor

All the very best and good luck.

Yes surely you will get seat in the IITS and NITs easily. Please aware of the notification given by them and act accordingly. I suggest you to apply for most of them then the probability of getting seat will increase.