Bring a large saucepan 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 frypan 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 capsicum. Cook 3 minutes over medium heat then reduce heat and simmer 5 minutes or until vegetables are tender. Serve over fettuccine.