Android as HTML5 kiosk/appliance
You can do that with the Nook, first thing is to get access to the Nook SDK, (not just android here):

https://nookdeveloper.barnesandnoble.com/

Next, you'll want to disable the home button, Stack Overflow has a good thread on this:
https://stackoverflow.com/questions/2162182/android-is-it-possible-to-disable-the-click-of-home-button

Lastly when setting up your Nook-esk Kiosk be sure to set it up in a way to keep it plugged in.  Kiosks should always be powered, and a full battery drain will reboot the whole OS.