I have an project from when I 'had' one in mine. Click the wrench by my name. However, I replaced it with a GPS with MP3 capacity.
Separate from my old install, I encourage you to look into RAM Mounts. See the link below for their web site.
With respect to their ease if installation (and ability to freelance the install), see: <A HREF="http://www.kachurak.com/7200/">http://www.kachurak.com/7200/</A>.
In addition, I routed the wires through the console. See: <A HREF="http://www.kachurak.com/7200i/">http://www.kachurak.com/7200/</A>.
For parts for the iPod Nano, see: <A HREF="http://www.gpscity.com/apple/ipod-nano/portable-music-mount.htm">http://www.gpscity.com/apple/ipod-nano/portable-music-mount.htm</A>.
They list a cradle for the Nano, but no photograph. I would suspect it is the same as the cradle in the suction cup mount, but without the arm.
If you were to go this route, you'd essentially do the same install as me, except possibly use a smaller arm and different cradle with ball receptacle.
Whatever you do - best of luck. If you have questions, e-mail me as I likely will forget to check this thread.