The Nook Color hardware is pretty dated by now, so you might find that running CyanogenMod 10 on it is a bit laggy. Instead, you might like to run CyanogenMod 7, which is well supported and much more responsive on it.
The steps to install CM7 to SD card on Nook Color is the same as in How to install CyanogenMod 10 to SD card on Nook Color. There are only two differences:
Instead of the CM10 ROM, download the latest stable CM7 ROM from here.
Download GApps that matches the version of CM7 ROM from here.
Using these files, follow the rest of the steps in the CM10 guide and you should have CM7 zipping on your Nook Color in a few minutes :)
Tried with: Nook Color 8GB, generic-sdcard-v1.3-CM7-9-10-larger-Rev5, cm-7.2.0-encore and gapps-gb-20110828-signed