Heat a large pot or Dutch oven over medium heat. Add a drizzle of olive oil.
Add the diced onion and bell peppers. Sauté for about 3-4 minutes or until they begin to soften.
Add the shredded rotisserie chicken to the pot and stir to combine with the vegetables. Sauté for an additional 2 minutes.
Sprinkle in the cumin, chili powder, garlic powder, and cayenne. Stir well to coat the chicken and vegetables with the spices.
Pour in the canned chili beans, drained pinto beans, and diced tomatoes (including the juice). Stir to combine.
Add the chicken stock to the pot. Stir everything together and bring the mixture to a simmer.
Reduce the heat to low, cover the pot, and let the soup simmer for about 15-20 minutes to allow the flavors to meld together.
Taste the soup and adjust the seasoning with salt, black pepper, and additional cayenne if you prefer more heat.
Serve hot, garnished with shredded cheese, chopped fresh cilantro, or a dollop of sour cream, if desired.