Hello aspirant
Getting a seating in nit has nothing to do with iits for admission in iits you must have to give jee advanced exam for undergraduate and gate for post graduate . you will have to fetch good rank in these exam to get a seat in iits. There is no any separate exam for nits students by which you can get into iits.
You can appear for jee main next year and if you qualify you can give jee advanced . if you get good rank in advanced you can get admissions in iits.

Exam which can get you a seat in iits
1. Iit jam
2. Jee advanced
3. Gate
4. Cat

Hope this will help

You can read more about admissions in iits from here
https://www.google.com/amp/s/engineering.careers360.com/articles/jee-advanced/amp

Best of luck.

Hi aspirant,

Once you have taken admission into NITs then you have two ways through which you can get admission into IITs. One way us that after getting admission in NITs, keep preparing for next year examination and then appear in JEE Advanced by qualifying JEE Main. Once you crack JEE Advanced you will have to withdraw admission from NIT and can get into IITs.

The second way is to complete your B.Tech and opt for higher studies. You can appear in examination like GATE or other and them get into IITs.

Hope it helps you.