Brown ground beef in a large skillet, stirring until it crumbles; drain. Stir in macaroni, 1/4 cup green onions, seasoning mix, and salsa con queso; pour into a lightly greased 13- x 9-inch baking dish. Sprinkle with crushed taco shells.
Bake at 350° for 30 minutes or until thoroughly heated. Sprinkle with remaining 1/4 cup green onions.