Hello Upendra, 

You have a good chance at getting in NSIT delhi with your JEE Main scores.  Assuming that your rank is somewhere between 50,000 and 75,000, there are numerous subjects you can get admitted into. Since you did not mention a particular subject,  I cannot give you a more specific answer.  You can see the institution's JEE Mains cut off ranks ( of various levels of counseling for various subjects)  for the OBC category here :  https://www.collegepravesh.com/cutoff/nsit-delhi-cutoff-2018/

Hope this helps :)