Has anyone given cbse board exam after giving NIOS too?

I am very much confused because I had planned to give NIOS as a backup this year and my main goal was to clear rt as a private candidate next year

But someone said That my CBSE marksheet will get invalid As I have to give it to NIOS for TOC but I thought I could just use the one with better marks

So please clear this doubt of mine and I had already googled and it said that both will be valid but I want to hear it from someone who actually knows about this