1Cook noodles to desired doneness as directed on package. Drain and rinse with hot water.
Heat oven to 350. Grease 2 quart casserole.
In large bowl, combine noodles, tuna, water chestnuts, celery, onions, mayonnaise, sour cream, thyme, and salt.
2Spoon half of tuna mixture into prepared casserole; top with 1/2 cup sliced zucchini. Repeat layers. Arrange tomato slices on top of casserole; sprinkle with cheese. Bake for 30-40 minutes or until hot and bubbly.