Bring a large pot of lightly salted water to a boil. Add pasta, and cook for 8 to 10 minutes, or until al dente; drain.

While pasta is cooking, melt cream cheese and butter in a skillet over low heat. Stir until smooth. Stir in milk, and season with garlic powder, salt, and pepper. Simmer for 3 minutes, or until thickened, stirring constantly.

Mix in chicken, broccoli, zucchini, and red pepper. Cook 3 minutes over medium heat, then reduce heat, and simmer 5 minutes, or until vegetables are tender. Serve hot over fettuccine and top with grated Parmesan cheese.