Place chicken breasts at the bottom of a slow cooker.
Add rice, black beans, corn, chicken broth, diced tomatoes, onion, garlic, and seasonings on top.
Stir gently to combine, ensuring rice is submerged in liquid.
Cover and cook on low for 6-8 hours or high for 3-4 hours until chicken is cooked through and rice is tender.
Remove chicken, shred it with two forks, then return to the slow cooker and mix well.
Serve in bowls with your favorite toppings.