Melt the margarine in a large skillet over medium-high heat. Cook sausage and chicken with the Creole seasoning until the meat is about halfway done. Add the mushrooms, green onion, green pepper and red pepper. Saute over medium heat until the mushrooms begin to shrink, about 10 minutes.
Stir in the chicken broth and milk, season with lemon pepper and garlic powder, and reduce the heat to medium-low. (Now is a good time to start boiling water for the pasta.) Mix together the cornstarch and cold water until dissolved - I like to use a coffee mug. Stir into the skillet. Cook, stirring gently, until the sauce returns to a boil. Boil for one minute, then remove from heat and set aside. Serve hot over cooked pasta.
Place pasta in a large pot of lightly salted water. Boil for 8 to 10 minutes, or until pasta is al dente. Drain.