Warm the pot: Set a large pot or Dutch oven over medium heat.
Add 1–2 tablespoons olive oil.
Sauté aromatics: Add diced onion and bell pepper. Cook 4–5 minutes until softened, stirring occasionally. Add garlic and cook 30 seconds until fragrant.
Add spices: Sprinkle in taco seasoning, cumin, and chili powder.
Stir to coat the veggies, letting the spices toast for 30 seconds.
Build the base: Pour in chicken broth, diced tomatoes, and tomatoes with green chiles. Stir well, scraping the bottom of the pot to release any browned bits.
Add chicken and veggies: If using raw chicken, add the breasts or thighs now. Add black beans, pinto/kidney beans, and corn.
Bring to a gentle boil.
Simmer: Reduce heat to medium-low and simmer 12–15 minutes if using raw chicken, or 10 minutes if using rotisserie chicken. Keep it bubbling gently, not a hard boil.
Shred the chicken: If you added raw chicken, remove it to a cutting board when cooked through (165°F). Shred with two forks, then return it to the pot.
If using rotisserie chicken, stir it in now.
Finish and season: Stir in lime juice. Taste and add salt and pepper as needed. If you want it thicker, simmer uncovered 5–10 more minutes.
Serve: Ladle into bowls and top with your favorites: cheese, avocado, cilantro, sour cream, tortilla chips, or a squeeze of hot sauce.