Begin by chopping the onion and bell peppers into small, even pieces. Set aside.
Heat a tablespoon of oil in a skillet over medium heat. Add the diced onion and bell peppers, sautéing for about 5 minutes until they become soft and fragrant, with a slight caramelization around the edges.
While the vegetables cook, trim the chicken breasts into 1.5-inch chunks. Once the vegetables are ready, transfer them to the slow cooker.
Add the chicken breasts on top of the vegetables inside the slow cooker. Pour in the canned diced tomatoes along with their juices, followed by the chicken broth.
Sprinkle the chili powder, cumin, smoked paprika, and a pinch of salt and pepper over everything. Stir gently to distribute the spices evenly.
Cover the slow cooker and set it to low. Let it cook for 6 to 8 hours until the chicken is tender and easily shredded, and the flavors meld together beautifully.
About 30 minutes before serving, open the lid and check the chili. If you prefer it thicker, remove the lid and turn the slow cooker to high for about 10 minutes to reduce the liquid slightly.
Use two forks to shred the cooked chicken directly in the slow cooker, stirring to combine everything well. Taste and adjust salt, pepper, or spice levels as needed.
Finish by stirring in chopped fresh cilantro and a squeeze of lime if desired, adding brightness to the dish. Serve hot in bowls with lime wedges on the side.
Enjoy your hearty, flavorful crockpot chicken chili, perfect for cozy weeknights or feeding a crowd with minimal effort!