In a large skillet, cook beef over medium heat 6–8 minutes or until it is no longer pink, breaking beef into crumbles.
Stir in the macaroni, broth, milk, ketchup, steak seasoning, mustard and onion powder; bring to a boil. Reduce heat; simmer, uncovered, 10–15 minutes or until macaroni is tender. Stir in cheese until melted. Sprinkle with chives.