Spray a large non-stick skillet with cooking spray. Cook ground turkey until brown. Add turkey pepperoni to pan during the last few minutes to cook along with ground turkey. Turn off heat and add parmesan cheese, garlic powder, and Italian spices. Chop green bell pepper and onion to desired size.
Open cans and drain. Add to crockpot, followed by meat and pepper/onion mixture (add chili seasoning for added heat, and/or sweetener to bring out the sweetness of the tomatos if desired). Stir until everything is well combined, and place top on crockpot. Cook for 4-5 hours on high heat (or until peppers are tender), or for 8 hour on low heat. Serve with additional parmesan cheese if desired.