This is my cheat-sheet from previous, successful cm9 and cm10 installs:
1. Using Win32DiskImager, burn
to a FAT32-formatted Sandisk class 4 microSDcard.
2. Eject then reinsert microSDcard.
3. Copy cm zip file to the microSDcard.
4. Eject and remove microSDcard.
5. Put microSDcard into powered-off Nook. Turn Nook on.
Wait for penguin to install software and turn Nook off ("... shutdown").
6. Move microSDcard back to PC. Copy gapps zip file to microSDcard.
7. Eject and remove microSDcard. Put microSDcard into powered-off Nook.
8. Turn Nook on. Wait for quick screen flash, then hold down Nook key.
9. On boot menu, use volume-down then Nook key to select "SD Card Normal"
10. After Nook starts, go to File Manager:
a. Turn on Root access mode (Settings->Access Mode)
b. Navigate to /system/app
c. Select and remove GoogleHome.apk and Hangouts.apk symbolic links.
11. Reboot. Wait for quick screen flash, then hold down Nook key.
12. On boot menu, select "SD Card Recovery"
Wait for penguin to install gapps and turn Nook off.
13. Repeat steps 8 and 9
Thanks in advance. BTW, kudos to the developers for their excellent work.