If you look at how it went with Universal Sports Network, you wouldn't hold your breath.If more people ask for it and demand it on social media and on sites like this, the big wigs will listen and begin entertaining the idea of having CBSN as a .3 (at least on CBS Owned and Operated stations) once they loosen some of their bitrate requirements for O&Os.
That said, NBC is a bit player in USN ownership.