Although I usually read books on paper on the iPad, I downloaded the Nook app for OSX this evening. Downloaded just fine, opened fine, but never made it past the splash screen. The animated “Nook” logo flashed across, froze, and sat there. For a long time.
Restarted several times with the same result, even downloaded it again and reinstalled with the same results. As of right now, the latest version is 3.0.0 which was released in March 2012, so not a lot of recent work has gone into it. Some google searches resulted in quite a few other people having the same problem with no real answer or updates from the B&N folks.
The solution as it turns out, is a very easy fix. In your /applications/ folder (where the Nook app is installed) create a new folder, call it “NookforMac” and drag the app in there. Make sure the app is closed, re-open it, and viola. Should work just fine.
Credit to kateB over at openkase for the workaround.
Update: Well, this solution worked for about a week, then the problem returned. The solution for that was to wait until the app launched, and froze on the nook animation. Right clicking in the grey-space around the logo and selecting ‘reload’ got the app to load the rest of the way (although it took a couple of times).