Heat 2 tablespoons olive oil in your large pot over medium heat. Add the diced onion and bell pepper. Cook for about 5 minutes, stirring occasionally, until softened and fragrant. Toss in the minced garlic and cook for another 1-2 minutes until aromatic.
Sprinkle in 2 teaspoons ground cumin and 1 teaspoon chili powder. Stir well to coat the veggies in the spices, cooking for about 1 minute to release flavors.
Add 6 cups chicken broth, 1 can diced tomatoes with juice, rinsed and drained black beans, and corn kernels. Stir and bring to a simmer.
Once simmering, add 2 cups cooked shredded chicken. Simmer for another 10-15 minutes to meld flavors.
Season with salt and pepper to taste, adjusting as needed.
Turn off heat and stir in the juice of 1 lime to brighten the soup.
Ladle soup into bowls and top with diced avocado, fresh cilantro, crunchy tortilla strips, and optional grated cheese.
