NIT

Please mention which NIT you are targeting so that I may be able to populate relevant details regarding eligibility. General eligibility criteria for getting admission in NITs for BE/B.Tech is:
Required criteria based on class 12th / equivalent qualifying examination:
1-Language,
2-Physics,
3-Mathematics,
4-Any one of (chemistry, biology, biotechnology, technical vocational subject), 5-Any other subject.
With at least 45% marks (40 % in case of candidate belonging to reserved category) in each of the subjects.

Please refer to the link provided below for a detailed list of courses offered by NIT, Nagpur and their eligibility criteria and admission process followed for these courses.
https://www.shiksha.com/college/nagpur-institute-of-technology-42631

You can apply for JEE Mains but not for JEE Advanced because your percentage is less than 75%, but JEE Mains 2018 exam got over on 5/4/18.

Depends on your category. If you are from general category, you might not get any NIT with these marks. Prepare for Advance, and do well to create better chances for you.

For IIT u will have to give JEE Advance and on the basis of JEE main u can get NIT and other gov or private college.

Paper 2 marks is not considered to get in NITs. Your paper one mark will decide, whether you will get in or not.

It depends on your rank, and the result will only be sure after counselling. As you said about the score, there is a chance that you may get a college. But, not so sure about it. So, wait for the result, and if you have any other exam, do your best.

There are very less chance to get any good NIT in this marks. But you can try lower branch in new nits.
you can get NIT PATNA
NIT SHRINAGAR

Hello Lalu,
For SC category, this is not a bad score. But I am not sure that you can get a good college with this score. So, you may try in the counselling round.
All the best.

You might get NIT - Srinagar, Patna but you should focus on advance.