Hello,

Rank is predicted on the basis of marks. That is for All India Rank. For categorical rank it totally depends on the board how they will formulate the rank pattern for categories. Even you have high percentile the chances are low for getting into a NIT. If your rank is below 1k then you can get into NIT. else you have to go for other colleges.

You can check the official website of the board to know the  details.

hope it helps!