Preheat the oven to 400 degrees. In a large bowl, toss the vegetables and chicken sausage. Add the olive oil, Italian seasoning, garlic powder and salt and pepper. Stir to completely combined. Lightly spray a rimmed baking sheet with cooking spray and transfer the vegetable and chicken sausage mixture to the baking sheet. Cook for 20 minutes, stir the mixture, and cook for an additional 20 minutes, or until the vegetables and chicken sausage are golden brown. Serve with a side of rice or pasta.