1. Heat oven to 350°F. Grease bottom and sides of 13x9x2-inch baking pan.
2. Combine pretzels and melted butter in small bowl; press evenly onto bottom of prepared pan. Spread sweetened condensed milk evenly over pretzel layer; layer evenly with chocolates, marshmallows and pecans, in order. Press down firmly on pecans.
3. Bake 20 to 25 minutes or until lightly browned; cool completely in pan on wire rack. Cut into bars. Makes 24 to 36 bars.