As of now, the criteria for NIT admission is securing 75%+ in 12th or any equivalent examination and admission is only done through the JEE results.
However, IIIT-Hyderabad takes admissions by the following:
Direct Admission for Student Abroad
Undergraduate Engineering Entrance Examination
Olympiad. This is only if you are selected to represent India on a national Level. You can apply for CSD, CND and CLD.
Lateral Entry for Dual degree for second-year college students in the CSE or ECE stream.
Hope I was helpful and good luck!
Government colleges likeIIT,NIT and IIITtake admission based on JEE rank. You have to appearJEE Mainsto get admission with a very good rank.