iPod nano not iPod OS, not iOS, something new?

Is it possible the new iPod nano isn’t running iOS, but isn’t running the old iPod OS, either? The latest firmware has hit Apple’s servers so developers are tearing into it and here’s what Steven Troughton-Smith had to say on Twitter: The nano codename is N20 it appears; also labelled as “1.0″ of the OS. Definitely not iOS. Rusty Mercury also says it’s running on a Samsung S5L8723, a step up from the previous Samsung 8730.

So what is this OS 1.0? something new? Something hybrid?