Dear candidate, I am considering you got 18000 rank in AIR(general) category. Then in OBC it will be around 3000. At this rank, you can easily get CSE in:

• NIT Allahabad
• NIT Jaipur
• NIT Hamirpur
• NIT Kurukshetra
• NIT Durgapur
• NIT Silchar
• NIT Puducherry
• NIT Jamshedpur
• NIT Patna
• NIT Delhi

For more details, you can visit: https://engineering.careers360.com/articles/nits-cutoff-for-b-tech-computer-science-and-engineering

Hope, it helps!