I just want to point this out, but there's a big difference between ipod nano 2g and ipod nano 2gb.
2g means second generation. Second generation ipod nano's can't be used to jailbreak.
On the other hand, 2gb means 2 gigabites (obviously), and if it's 2gb then I'm pretty sure it's a 1g (generation, as stated above, just writing it again so there's no confusion). But I could be wrong. A quick google search should help you decide which one you have. Anyways, if it IS infact an ipod nano 1g, you can jailbreak with it.
Just install rockbox on it, decide what backup manager you want, grab the payload you want and you're set. If that's too much work for you, I can upload my .rockbox folder on my ipod 1g for you. Good luck