NIT

I cannot comment about SPA or IITs, but NIT admissions are solely based on your JEE Mains paper. Only your AIR in Mains are considered not of JEE advanced.
PS: I am assuming that the Paper 2 specified in your question implies JEE advanced paper 2.

NIRF rankings says it all.
By the way, In NITs Trichy, Warangal, Surathkal, Rourkela, Durgapur (only mechanical), Allahabad (except Civil) are considered one of the best.
In IITs, Kanpur, Madras and Guwahati are best for research purpose study. Placements are good in all of top 8.

If you're from general category, you will middle order ranked colleges like, NIT Durgapur
NIT Jamshedpur
NIT Surat
NIT Hamirpur
NIT kurukshetra
If OBC, then
NIT Allahabad
NIT Calicut
NIT Rourkela
NIT Jaipur
NIT Nagpur
NIT Bhopal
If SC or ST, then you will get top ranked colleges as
NIT Trichy
NIT Warangal
NIT Surathkal
All the best.

Hello Manikanta, You can normally take admission in colleges of your state of private deemed to be universities if you elliminate IIT's. I am attaching a link that will give you all the required information.
https://www.shiksha.com/b-tech/ranking/top-aeronautical-engineering-colleges-in-india/49-2-0-0-0

It's worth trying. There will be GD & PI round after which you can apply.

No, you can't. It is because you need to have 75% atleast in your class 12th board exams.

Hi, With your CAT score, you will not be able to get admission in any Nits.

You don't have to worry about % of boards, because minimum % required for admision in NITs is only 60% for SC/St. And, the JEE rank only depends on your JEE score not on your boards percent.

More than 180 if you are in general category candidate otherwise you need to score more than 150 if you are an OBC category candidate.