JEE Scores

I am not sure of you getting top NITs but you can get NIT Srinagar, NIT Silchar, SVNIT with your given marks. Other than these you can also get the below mentioned colleges

Vishvajeet !answer this question would be tough as it totally a personal decision.in my opinion,you must go for some premier private institute that are doing exceptionally well.They along with good education provides an assured placements.so why to waste an year when you can invest that time i research and projects.here are following such institutes where they provide you an international exposure to shape your career in an excellent manner.i have recommended some colleges.Lovely Professional University venture in their students an unmatched entrepreneurial skills that make their students an easily employable.
hope it helps!

With this score you can't get any govt institute but in private ones you can get good colleges like Jaypee Institute of Engineering and Technology, Galgotia, UPES Dehradun, UTM Shillong & MNIT Bhopal.

there is a chance

There is no chance.

Yeah,Off course you can do B.Tech but on the basis of class 12 marks.
Best of Luck

I assume you as general category as Agrwal's usually are. So honestly no chance of Nit's better checkout some good colleges in your home state. You have a fair enough score to get those colleges.

Very low chances look for private colleges.