1. Prepare the ingredients by dicing the onion and gathering the chicken breasts, black beans, corn, diced tomatoes with green chilies, chicken broth, taco seasoning, and cream cheese.
2. In a slow cooker or large pot, add the chicken breasts, drained black beans, corn, diced tomatoes with green chilies, diced onion, and chicken broth.
3. Sprinkle the taco seasoning over the ingredients and stir to combine everything evenly.
4. If using a slow cooker, cook on low for 6-8 hours or high for 3-4 hours. If cooking on the stovetop, simmer on low heat for about 30-40 minutes until the chicken is fully cooked and tender.
5. Once the chicken is cooked, remove it from the soup and shred it using two forks.
6. Return the shredded chicken to the pot and stir to combine with the soup.
7. Cut the cream cheese into small cubes and add them to the soup, stirring until fully melted and blended into the broth.
8. Let the soup simmer for an additional 5-10 minutes, stirring occasionally to ensure a creamy consistency.
9. Taste the soup and adjust the seasoning with additional salt, cumin, chili powder, or garlic powder if desired.
10. Serve hot and top with shredded cheese, avocado slices, chopped cilantro, tortilla strips, or sour cream as desired.
11. Store any leftovers in an airtight container in the refrigerator for up to 5-7 days or freeze for later use.