Combine quinoa, enchilada sauce, black beans, diced tomatoes, sweet corn, onions, chicken (optional), and water all into crockpot and stir.
Leave crock pot to cook on low for 6-8 hours, stirring occasionally and until liquid is absorbed and the quinoa is tender.
Add ½ of the divided cheese.
If you added chicken, remove from crockpot and shred it with a fork and put back into crock pot for an additional 30 minutes to an hour.
When finished, prep lettuce cups onto plate and dish up quinoa dish inside cups. Serve with any desired toppings: remaining cheese, cilantro, avocado, and your favorite hot sauce. ENJOY!