Preheat oven to 400°F.
Wash and prepare the peppers by cutting them in half and scooping out the seeds.
In a bowl, mix tomato sauce with ½ teaspoon Italian seasoning, kosher salt, and pepper.
Heat skillet over medium heat. Add turkey, sausage and onion. Cook until no longer pink.
Add garlic, cook 1 minute. Add 1½ cups tomato sauce mixture, ½ teaspoon Italian seasoning, and rice. Stir.
Fill each pepper with rice mixture. Then top each pepper with remaining tomato sauce. Pour chicken broth into slow cooker and secure with lid.
Cook on High for 3 hours. Top with cheese and return lid until cheese melts.
Optional: Place oven rack on bottom setting and set oven to broil. Place crockpot on bottom rack under broiler for 2 minutes to brown cheese.(optional)
Top with desired toppings (optional)