There are two main criteria to get admission into one of the NITs. One is to satisfy the board criteria and the other is JEE Main percentile/rank.

So, as you said, you have scored 338 then it calculates above 65% (out of 500), so you clearly satisfy the board eligibility criteria.

So, you can apply for JoSAA Counselling, on the basis of your rank and your category, you will get allotted a particular branch in a particular college as per the choices filled by you in the application.

Hope it helps.