Spray a skillet with cooking spray. Add the chicken sausage and cook for about 2 minutes on each side, flipping so that all sides are evenly cooked, so about 8-10 minutes total. Remove from skillet and cool slightly. Cut the sausage into bite-size pieces.
Meanwhile, add 2 tbsp. of vegetable oil to a large skillet. Add the onions and peppers and cook until tender, about 5-7 minutes. Add the tomato sauce, garlic powder, Italian seasoning, salt, pepper and cooked sausage. Cook for a few minutes until sauce is warm and thickened. Serve immediately.