Hello there @jeff! We do support a migration plugin from Discourse to NodeBB. The friendly folks at TDWTF have migrated successfully, and they were instrumental in getting the migration plugin completed.
It looks like @Ben-Lubar's fork is the most up-to-date, so you can find it here: https://github.com/BenLubar/nodebb-plugin-import-discourse
We can also handle the migration for you for a nominal fee, please contact us at email@example.com if you're interested.