Prep the ingredients: Start by cutting the chicken breasts into bite-sized pieces. Slice the smoked sausage and chop the vegetables — red and green bell peppers, onion, celery, and garlic.
Layer the slow cooker: Place the chicken, sausage, diced tomatoes (with juice), bell peppers, onion, celery, and garlic into the slow cooker. Add the Cajun seasoning, thyme, paprika, and black pepper. Pour in the chicken broth and give everything a good stir to combine.
Cook the jambalaya: Cover the slow cooker and cook on low for 4–5 hours or on high for 2–3 hours. The slow cooker will work its magic, infusing the chicken and sausage with all the delicious spices and creating a savory broth.
Add the rice: About 30 minutes before the cooking time is up, add the uncooked rice to the slow cooker. Stir it into the mixture and cover. Let it cook for the remaining time, allowing the rice to absorb the broth and flavors.
Finish and serve: Once the rice is cooked and the dish is thickened, give everything one last stir. Taste and adjust the seasoning, adding salt if necessary. Serve the jambalaya hot, garnished with fresh herbs or green onions if desired.