Preheat oven to 350°. Cook macaroni according to package directions.
Meanwhile, in a large bowl, combine chicken, soup, cheese, spinach, mayonnaise, basil, garlic powder, thyme and pepper.
Drain macaroni; gently stir into chicken mixture. Transfer to an ungreased 2-½-qt. baking dish. Toss bread crumbs and butter; sprinkle over casserole.
Bake, uncovered, until bubbly, 40-45 minutes.
