Add all ingredients except the tortilla chips and optional garnishes to the slow cooker. Stir them together and set the slow cooker on low for 8 hours.
Before serving, add the crushed tortilla chips into the soup and let them soak up some of the liquid.
Top with shredded cheese, cilantro, or other favorite toppings.
Serve Slow Cooker Chicken Tortilla Soup with side salad.