1Line 13x9-inch (3-quart) baking dish with cooking parchment paper, and spray with cooking spray. Set aside.
2In 4-quart saucepan, melt butter over medium heat. Add marshmallows. Stir with wooden spoon or rubber spatula until marshmallows are fully melted. Reduce heat to low; stir in cereal until evenly coated. Remove from heat; pour into baking dish. Use greased rubber spatula or greased hands to press mixture firmly and evenly in dish. Refrigerate 15 minutes.
3In 2-quart saucepan, cook caramels, milk and salt over medium heat, stirring frequently, until caramels are melted. Pour mixture over bars, and spread evenly. Refrigerate 10 minutes.
4In double boiler over medium heat or in microwavable bowl in microwave, melt chocolate chips. If using microwave, microwave uncovered on High in 30-second increments, stirring after each, until melted. Pour melted chocolate over caramel; spread evenly. Sprinkle with pecans. Refrigerate until set, 1 to 2 hours. Cut into bars.