Yes if u secure a good marks as well as a rank as per cutoff u will get admission in Nits & IITs after  both the paper done for jee 2021

If you give JEE MAINS 2021, Then surely you can get admission into IIT and NIT. But There are only 2 attempts where you can get into IIT.

So If your 2 attempts are gone then You can't go for IIT but for NIT You can try there too.

So Let's Wait for the Result and Hope for the Best You will score well.

ALL THE BEST :)