Preheat oven to 350 degrees F. In an extra-large bowl, stir together chicken, celery, carrots, sweet pepper, mushrooms, almonds, and pimiento. Add soup to chicken mixture; mix well.
Transfer chicken mixture to an ungreased 3-quart rectangular baking dish. Bake, covered, for 45 minutes. Sprinkle with chow mein noodles. Bake, uncovered, for 5 to 10 minutes more or until heated through. Makes 8 servings.