I got 51 marks in jee mains (sc reservation), did i get any seat in nit or iiits.

Hello Aspirant

It is difficult to predict the College because this jEE mains was conducted by NTA and exam was held twice and applicants will increase.
Once go through the rank predictor.you should login with your login credentials:
https://www.google.com/amp/s/engineering.careers360.com/articles/jee-main-rank-predictor

NITS cutoff link:
https://www.google.com/amp/s/engineering.careers360.com/articles/jee-main-cutoff-for-top-nits

IIIt's cutoff link:

https://www.google.com/amp/s/engineering.careers360.com/articles/jee-main-cutoff-for-top-iiits

By rank predictor you can know ranks for your score
then compare with nits and IIIt's cutoff rank.
If you have any questions further let me know.
Thank you!!!

The cutoffs vary every year depending upon various factors like number of students appearing for the exam, difficulty of paper set, etc.

The actual cutoffs for the institutes category wise will be released after the results are announced (Tentatively it will be announced on 31st January 2019).

If you still have any queries feel free to ask in the comment section down below.