hello aspirant ...
No, it is compulsory that you clear NATA exam with at least 80 marks i.e 40%. Even if the college you are applying to takes JEE paper 2 scores, clearing NATA exam is a prerequisite. Yes, you can in get it in private colleges but not in government colleges.
hope it helps !
If you want your admission in any private college in India or even a govt. college you need to appear for NATA.
What happens is that during the admission process, colleges ask for your 12th standard marks and your NATA score, based on which your merit is decided.
For even colleges like CEPT, NATA is mandatory.
All The Best.