I have the same nano connected using the USB port in the center console and have no issues... My car is an '11 with the combox so I get track info along with t6he album art.
Is this something that just started, were you able o see the track info previously? Or is the car new to you and you are unable to get the track info to show?
2011 Space Grey E90 M3, DCT, Comp. Pkg.
1997 Z3 2.8, Artic Silver, Tanin Red interior, MT
1974 2002tii, Inka, 5 sp manual