Crockpot Quinoa, Sweet Potato, & Chicken Fajitas

uncooked quinoa, (rinsed thoroughly)

large boneless skinless chicken breast ((or 2 small ones; 3/4ths pound))

corn, (undrained*)

black beans (drained and rinsed)

EACH) petite-diced fire-roasted tomatoes, (not drained)

chicken stock or broth

sweet potatoes (peeled and chopped into small pieces)

and 1/2 cups sweet bell peppers, ((I used 1/2 an orange and 1/2 of a red pepper))

fajita seasoning mix

Flour or corn tortillas

Toppings: shredded cheddar cheese, low fat sour cream, cilantro, fresh lime, chopped avocado, guacamole, cherry tomatoes