Place the chicken breasts at the bottom of the slow cooker.
Add the black beans, corn, diced tomatoes, chopped onion, and minced garlic on top of the chicken.
Sprinkle the chili powder, ground cumin, smoked paprika, salt, and pepper over the mixture.
Pour the chicken broth over all the ingredients, ensuring everything is submerged.
Cover the slow cooker and set it to cook on low for 6-8 hours or on high for 3-4 hours.
Once cooked, remove the chicken breasts and shred them using two forks.
Return the shredded chicken to the slow cooker, stirring to combine with the soup.
Taste and adjust seasoning if necessary before serving.
Ladle the soup into bowls and top with tortilla strips, diced avocado, shredded cheese, and cilantro if desired.