Hello Yogesh,

For securing a seat in nits or IIITs you must give jee mains and qualify it with minimum cutoff marks. There is strict rule that for getting into nits IIITs , gfti's you must be having minimum 75% in 10+2 in pcm. And you should clear jee mains cutoff. Even qualifying cutoff is also not enough nowadays to get into nits, you have to score good to get good rank too. 

Ask if you have any query in comment section

hello 

yes you can get an nit even if you don't qualify jee mains as is the case with north-eastern nits where the students who are not qualified as per their category get the branches because of the home-state quota. feel free to ask any doubts in the comments section.