IIIT

You are likely to get NIT, but with average rank, LMNIIT with a decent branch, though don't go with NIT less than 15th position among them. Moreover, shortlist the colleges according to their last year cutoff.

It is likely that you will able to get it in spot round. Moreover, for the past year figure, you can use the college predictor. https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor.

Obviously, NIT always stood first, but IIIT also have a lot of placement opportunities, if you study well.

Straight forward answer. No. There is no such quota for direct admission. They are managed centrally and no scope of getting into that on direct basis. Only private colleges offer such quota. Hope it helps.

You'll not get a good deal, if you are not a reservation category student. If you are not, try private university and autonomous institutions through any quota. If you are in reservation, you are likely to get chemical in one of the top 10 NIT's. College Predictor:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=7489993.

Getting NIT is different, but getting a good NIT with decent branch is different. I would recommend not to go in NIT below top 13 ranking. Moreover, with you, are left with getting into private colleges or universities or try any autonomous institute. Try our college predictor:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=7489993.

Yes, you can go for it.

Hello Akshay,Use Shiksha College Predictor
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor.

Hello,
Please use Shiksha college predictor
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor.

Hello Gajula,
Your rank is not enough to get you a seat in any NIT, however, you will get some good private colleges, kindly check here.
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
All the best.