Yes! The NIOS certificate is valid for both the JEE MAINS & ADVANCED examination. So if you wish to take admission in any of the colleges through JEE MAINS, then your NIOS score will be valid. You have nothing to worry about the NIOS, the score card is widely accepted. The main thing which you should focus on is your JEE MAINS preparation. Giving mock tests is a key to success for this examinations. So keep on practicing mock tests.

For more information regarding the JEE MAINS preparation tips consider the link below:

https://engineering.careers360.com/exams/jee-main

For more information regarding NIOS consider the link below:

https://school.careers360.com/exams/nios-class-12

I hope this helps. Wish you a great day!