In a large skillet over low heat, melt cream cheese and butter; stir until smooth. Add the milk, garlic powder, salt and pepper. Cook and stir for 3 minutes or until thickened. , Add the chicken, broccoli, zucchini and red pepper. Cook over medium heat for 3 minutes. Reduce heat; cover and cook 5 minutes longer or until vegetables are tender. Serve with fettuccine.