Hello,

Actually possibilities are change every year just for some factors. Those are question difficulty level,  number of student appeared, number of student qualifying etc etc. But as per general basis,  if you scored 140 to 150+ in jee mains then your rank is near around 28k to 30k.

In that range of rank you have the chances for all top NITs. On the caste basis you have the chances for the further top institute also.

For more details check the following link

http://www.engineering.careers360.com/jee-main-college-predictor

Hope for the best.

Thank you.