First of all, JOSAA does not help an individual in getting a college. They just provide you with the best college you deserve at your rank if you have filled it in your preferences only if there is a vacant seat in the college. 

You are eligible for admission in any NIT if you have cleared the cutoff for JEE Advanced and have an aggregate of 75% in your 10+2 or is in top 20 preventive of your respective board.

Hope this helps!