Do they sell 2000 mAh nunchuck style batteries and the charger for them?

It's a 9v. Nunchuck style 2000 mAh battery

Last time I went there they did not sell any batteries besides AA, AAA, and 9v. They don't have any parts or batteries for airsoft guns. The local Airsoft players may have one you can buy though.

You will have to call them directly