Begin by prepping your ingredients. Dice the onion and bell pepper, and mince the garlic.
Place the chicken breasts in the bottom of the crockpot.
Add the black beans, kidney beans, corn, diced tomatoes (with their juice), taco seasoning, chicken broth, onion, bell pepper, and garlic on top of the chicken.
Season with salt and pepper to taste, if desired.
Cover the crockpot and set it to cook on low for 6 hours.
After 6 hours, carefully remove the chicken breasts from the soup. Shred the chicken using two forks, then return the shredded chicken to the soup and stir to combine.
Serve hot in bowls and add optional toppings as desired.
If you prefer a spicier soup, consider adding a diced jalapeño or a pinch of cayenne pepper.
This soup can be stored in the refrigerator for up to three days or frozen for longer storage.
Feel free to adjust the beans and veggies to your liking or based on what you have available.