Slow Cooker Chicken Tortilla Soup

Made this tonight and was quite pleased with the results. It's modified from a mothering.com recipe.

Ingredients:

1 onion, chopped
1 can pinto beans
1 can black beans
1 cup frozen corn kernels
1 (8 ounce) can tomato sauce
1 (12 fluid ounce) can or bottle beer
1 can diced tomatoes
1 small can diced green chilis
1 tablespoon chili powder
1/4 teaspoon garlic powder
1/4 teaspoon onion powder
1/4 teaspoon crushed red pepper flakes (or more or less to taste)
1/4 teaspoon dried oregano
1/2 teaspoon paprika
1 1/2 teaspoons ground cumin
1 teaspoon kosher or sea salt
1 teaspoon black pepper
2-3 whole skinless, boneless chicken breasts
1 red bell pepper, diced

topping ideas:
shredded cheese of choice (we didn't bother)
sour cream
crushed tortilla chips (could easily omit these if going low-carb)
chopped cilantro
sliced avocado (would have been divine if I had any in the house)

Mix all ingredients except chicken, bell pepper and toppings in slow cooker. Put chicken breasts on top and press down slightly to cover with liquid. Cook on low for 5 hours. Remove chicken and shred. Place back in slow cooker and cook another 2 hours on low. (This last step of cooking again wasn't really necessary, as my chicken was fully cooked after the 5 hrs on low. However, letting it cook again for a while on low did thicken it up some and gave a richer flavor). In the last 5 mins stir in bell pepper and continue cooking on low while you prepare toppings. You could also easily throw the bell pepper in from the beginning, but I prefer mine with a little crunch.

Serve in big bowls with plenty of toppings :)