My nano was working just fine and I had been using it as my fitness watch ( music). I plugged it in to charge and when I came back to unplug it, it was so hot that it burned my hands. I continued to unplug it and that was the last time it worked.

I had a similar incident. I have been using my nano for running and it gets sweaty as it is against my skin. I went to turn it on the next day and it was black. I thought it was flat as I tend to leave the music playing. I plugged it into my laptop to charge, however the lid was down. As I lifted the lid I saw the nano screen flash with the white apple logo like it dose when you first turn it on. I held the nano in my hand and felt that it was getting hotter. I thought it could of been the USB port so I swapped it for another one but the same thing happened. I changed it then to a wall plug in, alas this also made the nano hot. i have now booked it into the Genius bar, hoping they will be able to fix it as I have the feeling that I may of fried the battery. Hoping also that it has not damaged the nano.

The reason for the long explanation is that you seem to have never got a response to your message and I was hoping that you may of found a solution or by writing this arouse a response from someone.