It appears for the standard way you must use it like an eReader for Adobe DRM books;
authorize the Nook via ADE,
download them to ADE then transfer them.
See http://www.dummies.com/how-to/content/how-to-get-adobe-digital-edition s-and-overdrive-fo.html
You may be able to download other eReader apps such as Bluefire, Aldiko or Overdrive, which can be authorized directly from within the app.
Quite a few people have had authorization issues with Aldiko and Overdrive.