Lightly grease the slow cooker.
Place the chicken breasts in the bottom of the slow cooker.
Add the onion, garlic, diced tomatoes with green chilies, black beans, corn, chicken broth, taco seasoning, cumin, smoked paprika, salt, and black pepper.
Cover and cook on LOW for 5 to 6 hours or HIGH for 3 to 4 hours, until the chicken is fully cooked.
Remove the chicken and shred it using two forks.
Stir the uncooked rice into the slow cooker.
Return the shredded chicken to the slow cooker and mix well.
Cover and cook on HIGH for 30 to 45 minutes, or until the rice is tender. Stir once or twice during cooking if possible.
Sprinkle the shredded cheddar cheese over the top, cover, and let it melt for about 5 minutes.
Serve topped with avocado, cilantro, and a squeeze of fresh lime.