Hello student, 

I am sorry to say but by getting just qualifying marks won't take you to IITs, you need to have at least some more marks than the margin score. 

As of NITs it all depends on your Jee Mains rank. All factors like category rank and state quota will decide that which NIT you will get. 

So,  as of now without knowing your Jee Score it's hard to predict. 

Yes, but you need to have at least 8k category rank for NITs. 

Hope this will help. 

Thanks.