sorry to break the bad news to you but you probably can't.
the newer ipods (and iphones) uses a new hashing method for storing music on your ipod which has not been (correct my if i'm wrong) reverse engineered yet.
there was a project a while back called
ipodhash but apple has long since sent them a dmca takedown notice and the project has been halted. there are some copies of the source code floating around on wikileaks but i don't know how much use a normal linux user would get out of them.
on my older generation ipod nano (1st gen nano) i used to use
gtkpod before i got my iphone. you can maybe try that if you think your nano is
old enough. but also i don't think it will be possible to copy music off the ipod if that's what you are after but transferring to the ipod should work fine assuming your ipod is supported.
good luck.