Heat olive oil in a large pot or Dutch oven over medium heat. Add onion and cook until softened, about 5 minutes. Add garlic and cook for 1 minute more until fragrant.
Add chicken breasts or thighs to the pot. Pour in diced tomatoes, black beans, corn, green chilies, and chicken broth. Stir in chili powder, cumin, and oregano.
Bring the soup to a boil, then reduce heat and simmer, covered, for 20-25 minutes, or until chicken is cooked through.
Remove chicken from the pot and shred it with two forks. Return shredded chicken to the pot.
Season with salt and pepper to taste.
Ladle soup into bowls and top with shredded cheese and your favorite optional toppings.
For Slow Cooker: Add all ingredients except cheese and toppings to the slow cooker. Cook on low for 6-8 hours or high for 3-4 hours. Shred chicken and return to pot.
This soup is freezer-friendly. Let cool completely before storing in airtight containers.
Consider this a great option for meal planning, especially when paired with a simple side salad.