Just thought this is helpful. If you crash your ipod nano as I just did, you can reset it. I found a reboot your ipod nano explanation here. It seems easy to fix it when it is crashed:
1) You put the hold switch in “off” position, e.g. the ipod needs to be able to accept you pressing buttons 😉
2) You press the menu button and hold, then the middle button and hold – both together for about 10 seconds.
3) Your ipod nano restarts after the crash.
Hope that helps!