Thinking about it you're probably better off just buying a memory key and using that instead. For the price of a holder you could probably get a 4-8GB stick which will hold the same amount of tracks as your Nano. It's also smaller, more discrete and you don't have to worry about leaving it in the car.
Whether you're using an iPod or memory stick you navigate through your tracks through the speedo computer display. Oh and Fiat send you a memory stick when you buy a car from them... I think it's only 256-512MB... it's a funny little flip out thing
