Like I said I'm really new at this, hopefully it's ok to post this here but if not please let me know where would be more appropriate.

Perfectly fine, we're here to help!

but I've read even better things about Bazzite and want to give it a whirl.

Imo, you're right. Bazzite > Nobara. Just don't expect better performance. But yeah, image based distros like Bazzite are way easier to use and maintain themselves.
Just remember that those kind of distros are a bit different from mutable OSs, like regular Fedora.
If you need certain CLI or other tools not available in your software center, use Distrobox and try to not install anything on your host if possible.

My question is, am I able to download it to a usb and just do a clean install without issues or do I have to do anything beforehand. I originally installed Nobara using btrfs if that makes any difference.

They should have the same installer. Just install Bazzite the same as you did Nobara, and select "Free up disk space" or however it's called. That will wipe all the Nobara stuff.

In general, you shouldn't have any problems. In my opinion, Bazzite is one of the most user friendly distros out there. Just learn how to use containers if you do more advanced stuff, that's the biggest difference between that and other classic distros :)