In much the same way that many things changed with the 6th generation iPod nano, the way you restart or reboot it changed also.
If you need to restart your nano, or reboot it because it's frozen, hold down both the Sleep/Wake button (the one on the top right) and the Volume Down button (the one of the far left). You'll need to do this for 8-10 seconds.
The screen will go dark as the nano restarts. When you see the Apple logo, you can let go; the nano is starting up again.
Thanks to a software update, the 6th gen. nano can now also be completely turned off.
