Ipod Nano 7th Gen: Play one track then stop?

Consider everything on your iPod to be in a container... be it a container of songs, albums, playlists, what have you. You can have it play something only once, but it will advance to the next item in the container to play by default once it is done. This is why people suggested using a playlist with only one item in it.

Now I don't know if you have tried making a playlist on the go or not, but the iPod Nano is capable of doing so. Just go into your playlists section on your Nano and scroll up to the very top of the screen. It will allow you to create a new playlist ("Add") or edit an existing one ("Edit"). Just select Add and then select your content. You can then go into that playlist and clear the list and reuse it for any other content you wish to play only once, so it's not that much more involved than selecting something to play on the fly now, only it will stop once done unlike the other process.