In the OnePlus Nord 2 Reviewer’s Guide sent to members of the media, which acts as a resource for details about the device, OnePlus explicitly confirms this detail which was highlighted by Adam Conway on Twitter.
Operating System: OxygenOS based on Android 11/Color OS 11.3.Notably, OnePlus previously tried to steer the conversation away from ColorOS as regards to OxygenOS.A leaked document that surfaced in late June showed that OnePlus had directly told employees not to address questions regarding ColorOS.
As for how it’s visible within Android 11 on the Nord 2, the changes are minimal at best.