Yes you can give JEE as you have a fresh marksheet of 12 of year 2020. No matter if you appeared for JEE previously using your CBSE marksheet. Many student appear for 12 again to regain their JEE attempt so you can also its common in Kota.

Hello Ashuthosh Singh Chandel. Thanks for contacting Careers360 and we hope we will be able to answer your query. 

Note that JEE Advanced can be given only two times, that too, in consecutive years. One in the year if graduation and the other attempt, in the next year. 

So, I am afraid you are not eligible to write JEE Advanced 2019. But, you can definitely write JEE Mains 2019 using your NIOS marks sheet. 

Even, I think you will not be eligible to write BITSAT in the year 2019.

Hope this helps you and all the best!