It certainly should work.
The connections are a little confusing. The male micro-USB coming off the top suggests that you need to connect it to your nook, which would make the whole thing a little unweildy. Also, how is it charged? From a PC? From a AC/USB adapter?
I bought a couple of these:
http://www.dealextreme.com/p/usb-re...emergency-power-with-cell-phones-holder-44749
They're only 2000 mAh, but you can connect them to the nook with the proprietary nook USB cable. Even though they're rated at 1A, my nook recognizes as 2A...
Bonus: built in fold up wall charger.
Not-so-bonus: DealExtreme ships from Hong Kong. Delivery time is measured using the geologic time scale.