SPRAY 8-inch square pan with cooking spray; set aside. Mix corn syrup and evaporated milk in 2-quart saucepan. Add chocolate. Cook on medium-low heat until chocolate is completely melted, stirring constantly. Remove from heat.
STIR in powdered sugar, vanilla and pecans. Beat with wooden spoon until thick and glossy. Immediately spread into prepared pan.
REFRIGERATE 2 hours or until firm. Let stand at room temperature 15 minutes before cutting into 20 squares to serve.