Preheat oven to 350°F. Grease a 9 inch square pan with cooking spray.
In a large bowl, stir together Oreo cookie crumbs and sweetened condensed milk. Mix in Skor toffee bits and milk chocolate chips. Spread into prepared pan. Sprinkle with extra Skor toffee bits, if desired.
Bake for 25 minutes. Let cool completely before cutting into squares.