Step 1: Add the Chicken and Vegetables - Place the chicken breasts in the bottom of your slow cooker. Scatter the diced onion and bell peppers over the chicken, then add the minced garlic. Starting with the chicken on the bottom helps it stay tucked down in the broth where it can cook evenly and turn tender. Do not worry about making everything look perfect here. This is one of those dinners where you can move quickly, close the lid, and let the slow cooker take over.
Step 2: Pour In the Flavor Base - Sprinkle the taco seasoning over the chicken and vegetables. Pour in the enchilada sauce, then add the chicken broth. Give everything a gentle stir around the edges so the seasoning starts to mix into the liquid, but there is no need to fuss with it too much. The broth will slowly pull all those flavors together as it cooks, and the peppers and onion will soften into the soup until they are tender and sweet.
Step 3: Cook Until the Chicken Is Tender - Cover the slow cooker and cook on high for 3 to 4 hours or on low for 6 to 8 hours. The chicken is ready when it is cooked through and easy to pull apart with a fork. Slow cookers can vary a little, so use the timing as a guide and check near the earlier end of the range if yours tends to run hot. You are looking for chicken that feels tender, not dry or stubborn.
Step 4: Shred the Chicken - During the last hour of cooking, carefully lift the chicken breasts out of the slow cooker and place them on a cutting board or large plate. Shred the chicken with two forks while it is still warm. It should pull apart easily into soft, bite sized pieces. Return all of the shredded chicken to the slow cooker, including any little flavorful bits that land on the plate. That chicken has been soaking up the enchilada broth all afternoon, and you want every bit of it back in the pot.
Step 5: Stir In the Beans and Corn - Add the drained pinto beans, drained and rinsed black beans, and frozen corn. Stir gently until everything is combined. This is the point where the soup starts looking like dinner. The beans add body, the corn brings little sweet pops in each bite, and the shredded chicken makes the whole pot feel extra hearty. Let it cook for about 30 minutes before adding the cream so the beans and corn can heat through.
Step 6: Finish With Half and Half - Pour in the half and half and stir until the broth turns creamy and smooth. Let the soup cook for the remaining time, about 30 minutes to 1 hour, until it is hot all the way through. Keep the slow cooker on low or warm once the half and half goes in. High heat can sometimes make dairy look a little grainy, and this soup is at its best when the broth stays silky and creamy.
Step 7: Thicken and Taste - Taste the soup and add salt and pepper as needed. If you want a thicker texture, mix 1 tablespoon cornstarch with 1 tablespoon cold water in a small cup until smooth, then stir it into the soup. Let it cook for another 10 to 15 minutes until the broth thickens slightly. You do not need to make it very thick. A little body is nice, but you still want it to feel like a cozy soup that settles into the bowl.
Step 8: Build Your Bowls - Ladle the hot soup into bowls and bring out the toppings. This is where dinner gets fun, especially with kids around the table. Add shredded cheese so it melts into the hot broth, toss on tortilla strips for crunch, or finish with a spoonful of sour cream. I usually put out jalapeños for the grown ups and let everyone make their own bowl exactly the way they like it.