Preheat oven to 350. Prepare a 2-quart casserole dish with cooking spray; set aside. Cook mostaccioli pasta according to package directions except omit the salt. Drain. In a skillet, cook turkey, bell peppers, and onions until no pink remains in turkey and vegetables are tender. Stir in salt, oregano, cinnamon, 1/8 teaspoon nutmeg, tomato sauce, and garlic. Alternate layers of mostaccioli and meat mixture in prepared dish. Heat margarine in a saucepan over low heat until melted. Stir in flour and remaining nutmeg. Cook over low heat, stirring constantly, until smooth and bubbly; remove from heat. Boil and stir 1 minute. Spoon sauce over mostaccioli and meat mixture. Sprinkle with cheese. Bake uncovered for 35 minutes.