Place cooked sliced mini peppers, sliced yellow onion, whole peeled tomatoes and liquid from the can, chicken thighs, grated garlic, balsamic vinegar, salt, and italian seasoning into a slow cooker. Stir to combine ingredients.
Set to cook on low for 4-6 hours or high for 2-3 hours. Stir occasionally using your spoon to crush the whole tomatoes as you stir.
Ensure that the chicken has reached at least an internal temperature of 165F before serving.
Serve over rice or cooked pasta. Garnish with parmesan cheese and fresh basil.
