Hey there!

Well it is hard to predict about the colleges as admission to these institutes depends on various factors like:

1- Difficulty level of examination

2- No. of students appeared in exam

3- No. of seats available in institutes

4- Rank of candidate

5- Closing rank of programs

However we can get a rough idea of seat allocation by analyzing previous years trend.

---With 81 percentile and assuming your OPEN category, your rank would be anywhere in between 194370 - 218500, as per our JEE mains rank predictor tool

https://engineering.careers360.com/jee-main-rank-predictor

Also according to previous years data, the maximum closing rank at various NITs for general category for CS and IT program is around 6000-12000 considering home state quota.

To check previous years closing rank of NITs for CSE branch https://engineering.careers360.com/articles/nits-cutoff-for-b-tech-computer-science-and-engineering

For IT- https://engineering.careers360.com/articles/nits-cutoff-for-btech-information-technology

So, considering these data you have low chances for getting into NITs.

If you wish to know about the colleges in which you may get admission based on your score, use college predictor tool https://engineering.careers360.com/jee-main-college-predictor?utm_source=google-search&utm_medium=paid&utm_campaign=jee-main-clgpd

Thank you!