trouble charging iPod touch

I have 2 wall chargers from my iPod touch. When I plug it in it comes up in the battery icon a plug, instead of a lightning bolt. And it won't charge. And it's not fully charged but yet it has the plug instead of the lightning bolt. It happens with both chargers. Is there a problem with my chargers, or the iPod itself?

Does it charge when you sync it with your iTunes on the USB lead?

If that doesn't work, then it's the iPod.

See how that behaves. It might just require a simple reset.