Sauté the bell pepper, onion, and jalapeno (if using) in a large pot with a little bit of oil over medium heat until softened, about 5-7 minutes.
Add the chicken broth, diced tomatoes (with their juices), drained corn, tomato paste, tomato sauce, taco seasoning, chili powder, and minced garlic to the pot. Stir well to combine.
Bring the soup to a simmer, then reduce heat to low and simmer for 1-2 hours.
After simmering, stir in the shredded rotisserie chicken and heat through for about 15 minutes.
Season the soup with salt and freshly ground black pepper to taste.
Serve hot with your favorite toppings like corn chips or crispy tortilla strips, sour cream, vegan or fat-free cheddar cheese, and chopped red onion.