Prepare the Slow Cooker:
Add the chicken, sausage, onion, bell peppers, celery, and garlic to the slow cooker.
Add Seasonings and Liquids:
Add the diced tomatoes with juice, tomato paste, chicken broth, oregano, thyme, smoked paprika, cayenne pepper (if using), bay leaves, salt, and pepper. Stir to combine.
Cook:
Cover and cook on low for 6-7 hours or on high for 3-4 hours, until the chicken is tender and cooked through.
Add the Shrimp and Rice:
About 30 minutes before serving, stir in the rice and shrimp. Cover and cook on high for an additional 30 minutes, or until the rice is tender and the shrimp are cooked through.
Finish and Serve:
Remove the bay leaves and stir the jambalaya well. Taste and adjust seasoning with additional salt and pepper, if needed.
Garnish with chopped fresh parsley and sliced green onions before serving.