This year for the Jee rank computation, the board marks wont be considered. So 2017 admissions would be solely based on jee score. If you belong to SC or SC, you may expect some average NITs. But if you are from general category then don't just rely on NITs. Through JEE main score you can also get admission through states counseling. Since only jee score will be considered, I would suggest you to concentrate on JEE leading to better scores.

You can also check which college you can get based on your marks/rank through JEE Main college predictor. Click on the below link-

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

All the best !!