1. Place the boneless, skinless chicken breasts evenly at the bottom of your slow cooker. This ensures they cook thoroughly and absorb all the delicious flavors.

2. Add the rinsed and drained black beans, drained corn, undrained diced tomatoes, undrained diced green chiles, and chopped onion (if using) over the chicken. Spread them out to distribute the ingredients.

3. Sprinkle the entire packet of taco seasoning mix evenly over the ingredients in the slow cooker. This will infuse all the components with a rich, savory flavor.

4. Pour the chicken broth over everything in the crockpot. The liquid helps to keep the chicken moist and creates a saucy base for your bowls.

5. Cover the slow cooker with its lid and cook on high for 3-4 hours or on low for 6-8 hours. The chicken should be tender and easily shredded with a fork when done.

6. Once cooked, remove the chicken breasts from the slow cooker and shred them using two forks. Return the shredded chicken to the slow cooker and stir it into the bean and corn mixture.

7. Serve the chicken and bean mixture warm over cooked rice. Set out your favorite toppings for everyone to customize their own burrito bowl.