I assume that this is your JEE Mains rank as you have not mentioned it in the question.For 10615 rank or 3115 in obc,yes it is possible that you will get a good government college like NITs.You can also get there core branches as your rank is very good and you are a bright student.So don't worry for the college you can check on our college predictor for more details.

https://engineering.careers360.com/jee-main-college-predictor

Click on the link.

Thanks.