If making homemade tortilla strips: Heat about 1 inch of vegetable oil in a skillet over medium-high heat. Fry tortilla strips in batches until golden brown and crisp. Remove with a slotted spoon and drain on paper towels. Sprinkle lightly with salt. Set aside.
In a large pot or Dutch oven, combine the shredded chicken, chicken broth, diced tomatoes and green chilies, black beans, corn, diced onion, minced garlic, taco seasoning, salt, and pepper.
Bring the mixture to a simmer over medium heat. Cook for 10 minutes, stirring occasionally, to allow flavors to combine.
Reduce the heat to low. Add the cubed cream cheese to the pot. Stir constantly until the cream cheese is completely melted and the soup is smooth and creamy.
Stir in the shredded cheddar cheese until melted. Taste and adjust salt and pepper if needed.
Serve the creamy chicken tortilla soup hot, topped generously with your choice of crispy tortilla strips, avocado, sour cream, cilantro, and a squeeze of lime juice.
Notes
For a slow cooker version, combine all ingredients except cream cheese, cheddar, and tortilla strips in the Crock Pot. Cook on low for 4-6 hours. Stir in cream cheese and cheddar during the last 30 minutes of cooking.
If you prefer a less creamy soup, reduce the amount of cream cheese by half or omit it entirely.
Use leftover cooked chicken if you do not have rotisserie chicken available.