1Heat oven to 350º. Cook and drain noodles as directed on package. Mix noodles, tuna, pimientos, mushrooms, sour cream, milk, chives, salt and pepper in ungreased 2-quart casserole or square baking dish, 8x8x2 inches.
2Mix bread crumbs, cheese and margarine; sprinkle over tuna mixture. Bake uncovered 35 to 40 minutes or until hot and bubbly.