Sauté garlic, onions, and peppers in a pan with olive oil for 7 minutes. Transfer into the crockpot/slow cooker.
Add all other ingredients to the slow cooker including chicken broth, chicken breasts, corn, black beans, and your tomatoes. If you're using fresh tomatoes, blend them before adding to the slow cooker.
Cook on high for 4-5 hours or on low for 6-8 hours.
Remove the lid to the slow cooker and shred the chicken. Add the shredded chicken back into the pot and cook in with the lid off for a few minutes before serving with your favorite toppings.