HEAT oven to 375°F. In large bowl, combine salad dressing, mustard and oregano. Toss chicken in mustard sauce until coated. Reserve remaining mustard sauce. Arrange chicken in 3-quart baking dish. Bake, uncovered, for 30 minutes.
STIR soup, milk, hot pasta, squash and 2/3 cup Crispy Fried Onions into remaining mustard sauce. Spoon pasta mixture into baking dish, placing it under and around chicken. Bake 15 to 20 minutes or until chicken is done.
TOP pasta mixture with tomato wedges and top chicken with remaining onions. Bake 3 minutes until onions are golden.