Installing CM11 in 2019
Like some others in this thread, I have just bumped into an old Nook Color and decided I'd give it a spin. I picked it up at a Thrift Store for about $10 and thought it might make a decent weekend project to revive.
As others had mentioned, I installed CM11 M11 snapshot that I got from
here. After this, I installed the last available nightly for this device from the
CM archive. This worked like a charm, but gapps wouldn't install. What I ended up doing was using the tips thread linked in OP's signature and reading
section B5 to install CWM as an alternate recovery. After this, I booted up to the recovery and flashed my gapps from there. This worked like a charm and got me the Play Store. No idea what's going on with the original install script that won't let it run.
FWIW, while CM11 does work, it seems to be unbearably slow with gapps installed. I may end up trying to find one of the earlier CM versions around the web and running that instead, but since CM is dead it seems that most (if not all) the mirrors only have the last CM version that was released for the device (CM11). In any case, it's nice to know that Android KK is at least runable on this old tablet!
Edit: After trying out all the CM builds for this device (except CM9, as I couldn't find any working links for it), I can confirm that practically any version of CM works reasonably well on this device
without gapps. If you would like to use gapps and still have a reasonably good experience with this device, I would recommend the last nightly of the original CM10 release (cm-10-20130421-NIGHTLY-encore). If gapps isn't necessary for you, CM11 seems to run pretty well. CM7 is immaculate if you absolutely don't care about much app support, although it certainly is weird to use gingerbread in 2019. All in all, I'll probably stick with CM10 on this one, since having the play store is definitely convenient.
Edit 2: I stand corrected: trying to run any app from the play store on CM10 is extremely slow. Tried installing the ROM with no gapps and then installing the app and that worked much better. All in all, if you intend to use this tablet at all, I would recommend installing any of the CMs available for it and completely ignoring gapps. Do note that running CM7 with gapps is completely doable and usable, but it’s so old that you’ll have trouble getting anything to install.