Heat the olive oil in a large pot over medium heat. Add the onion, garlic, and bell peppers. Cook, stirring occasionally, until the vegetables are softened, about 5 minutes.

Add the shredded chicken, black beans, corn, diced tomatoes with green chilies, and taco seasoning to the pot. Stir to combine.

Pour in the chicken broth and bring the mixture to a boil. Reduce heat to a simmer and cook for 20 minutes, allowing the flavors to meld.

Season the soup with salt and pepper to taste. Serve hot, garnished with optional toppings like shredded cheese, sour cream, chopped cilantro, diced avocado, and tortilla strips if desired.