JEE Main Scores

Please compare with the cut-offs of the last year for NITK.
https://www.shiksha.com/college/national-institute-of-technology-surathkal-mangalore-24187/admission#admission

I think it is very difficult. But you may try some other colleges which give admission even if you are qualified in JEE Mains. I don't know the colleges exactly which provide such admission. In addition to that, it is also advisable to go for JoSAA options entry as many seats are being vacant in the past few years.

Dear Pradeep,
You cannot get any NIT as your marks are too low, but you can get any government or best private engineering college which you can get through state counselling or via direct admission. There are so many private colleges which provide better placements and education.

Yes, you should try applying. The results might surprise you.

Yes, MBM is a good engineering college located in Rajasthan. Placements are also good there. You should go for that.

Though you have good marks in boards, still you are unable to get into colleges through it. With your Mains score, getting into SSN is not likely to be in your favour according to your last year statistics or any of the top colleges as their ranking requirement is below 20K. Still, you can get a private university or try for home state autonomous colleges.

Use your WBJEE 2018 rank to see where you can get admission at the link provided below:
See the courses, colleges & rounds you may crack.
The result is based on admissions data of WBJEE 2017.
Get resources & insights on colleges & courses:
https://www.shiksha.com/b-tech/resources/wbjee-college-predictor

IET-Lucknow gives admissions on the basis of UPSEEE and not with Mains score. Kindly appear for the same to get into IET.
Best of luck.

No, you are not eligible for appearing in IIT. You can reappear for your intermediate exams. If you want to go for IIT Advanced, you need to reappear for all the subjects, whereas, if you want to clear JEE Mains then you can apply for the only PCM.
Eligibility for IIT:
60 % marks in PCM.
75 % total aggregate percentage. There are a lot of people who drop out and do IIT preparation due to social pressure. A little recommendation from my side.
Follow your passion.