Preheat oven to 350°F. Cook macaroni according to package directions. Drain noodles and set aside.
In large saucepan, melt 4 tablespoons butter over medium-high heat. Add flour and curry powder, whisk well, cooking for 1 minute or until fragrant and flour starts to smell nutty.
Add cold milk and whisk well to combine. Bring mixture to boil and continue to whisk occasionally as mixture thickens, about 4-5 minutes. Whisk in salt and pepper, add cheeses and stir until melted.
Add chicken, broccoli and cooked macaroni to cheese mixture, fold to coat and cook on stovetop over medium heat 5 minutes or until heated through. Pour mixture into buttered 9 x 13-inch baking dish.
Melt remaining 1 tablespoon butter; add bread crumbs and mix. Top macaroni mixture with buttered bread crumbs and bake 20 – 25 minutes. Remove from oven, let rest 5 minutes before serving.