My awesome husband got it working for me! In case anyone else has problems with Nook for Mac on 10.6.8 and higher, this is what he found, that finally worked for us!
The solutions didn't really work for me. I have a new MacBook Pro and did a clean install but no luck. I did get Nook Study for Mac to work for me though. Which only frustrates me more. I'm a sys/admin and I know that if they can get one app working they should be able to get the other one working as well.
Please, please don't leave your Mac customers out in the cold! We're want to BUY things from you. You've already got a good code base to work from and having a working app for your customers seems like good marketing and customer service to me.