This works for Archos because the '/system/app' directory has aliases to the '/data/test/froyo/system' folder. Basically, Archos sorta knew we'd manually install the Market.
If the Nook has something similar, it could work, but you'd have to see what writable directory the Nook has if they even do this like Archos.
If they don't have the files like this prefixed with a 0 then you'd probably need full root to get the market going. However, I'm not root expert to guide Nook users nor do I have a Nook... (=