Hey,

Generally you don't have to apply for other application form other than JEE for admission into NITs. There are few IIITs like IIIT-D, IIIT-Hyderabad, IIIT- Naya Raipur, IIIT- Bhubaneswar etc who conduct separate counselling for admission so you need to fill form separately for admission in these IIITs.

Candidates will be able to apply for IIIT Hyderabad B.Tech admission 2021 through four channels - JEE Main , DASA UG, SPEC, UGEE/KVPY/Olympiad.

Go through the link below to get further analysis-

https://engineering.careers360.com/articles/iiit-hyderabad-btech-admission

Hope this helps.