Insert stick into each apple. Line trays or baking sheets with wax paper; spray paper with nonstick cooking spray. Place chopped candy bars on separate plates or mix together on one plate.
Combine sugar, sweetened condensed milk, corn syrup and butter in medium, heavy-duty saucepan over medium-low heat. Heat, stirring frequently, for 10 minutes or until sugar has dissolved. Attach candy thermometer to inside of saucepan. Increase heat to medium; cook, stirring frequently, for about 20 minutes or until mixture reaches 236°F on thermometer. Remove from heat; stir in vanilla extract.
Dip apples all the way into caramel mixture, shaking off excess. Roll bottom half of apples in chopped candy bars, then place on prepared trays. Refrigerate for 1 hour or until set. Store apples in refrigerator in airtight container.