I am currently pursuing 1st year B.tech (CSE) in NIT Raipur. Can I give JEE Mains next year and take admission in another NIT or IIIT?

Yes, you can surely attempt your JEE Mains/Advanced/BITS. Many students do the same. There are (and have been) at least 1 or 2 such students in every batch of NIT Raipur.

But I would advise you not to opt for just any other NIT. Choose an NIT which is at least 5-6 ranks above NIT Raipur. Otherwise, switching to another NIT will prove ineffective. The same goes for IIITs, choose only the old ones.

This is because NIT Raipur offers decent placements for CSE, at par with the NITs of the same stature. So wasting a year for NIT Jamshedpur or NIT Durgapur will be fruitless. If you go for JEE counseling, you’ll have to withdraw from your NIT Raipur seat first. To be on the safe side, go for the counseling only with a score high enough to get you CSE in a better ranking NIT. Otherwise, you might get NIT Raipur once again. This has happened with students in the past.

I hope this advice will help you make wise decisions regarding your college switch.