HI Aspirant!
Congratulations on your JEE Main rank. According to previous year cutoffs and trends the closing rank in last round for OBC category, Outside Delhi region and for Mechanical Engineering are follows:

NSIT: 19418

DTU:19214

Hence by observing previous year trends we can predict that you can easily get Mechanical Engineering in either NSIT or DTU.

You can follow up this Career360's article for more information on cutoffs: https://engineering.careers360.com/articles/jac-delhi-merit-list

And don't forget to check out the Career360 College Predictor to know your college admission chances based on your JEE Main Rank, Home State, Caste, Gender, etc.

https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

HAPPY HUSTLING!