Assemble all ingredients before beginning to streamline the cooking process.
In a slow cooker, combine diced tomatoes with green chiles, chili beans, black beans, corn, beer, tomato sauce, and the chopped onion. Sprinkle the taco seasoning over the mixture and stir to integrate thoroughly.
Position the chicken breasts atop the mixture, gently pressing them so they are partially submerged in the liquid.
Cover the slow cooker and cook on a low setting for approximately five hours.
When the chicken is fully cooked, transfer it to a cutting board and allow it to cool slightly. Shred the chicken with two forks before returning it to the slow cooker.
Continue cooking on low for an additional two hours to ensure the flavors meld harmoniously.
Serve the soup piping hot, topped with shredded Cheddar cheese, a dollop of sour cream, and a sprinkling of crushed tortilla chips to enhance texture and flavor.