Line a 9-in. square baking pan with foil and grease the foil with 1 teaspoon butter. Arrange a single layer of crackers in the pan.
In a large saucepan, combine milk, brown sugar, corn syrup and remaining butter. Bring to a boil over medium heat, stirring occasionally. Reduce heat to maintain a low boil; cook and stir 7 minutes. Remove from heat. Evenly spread a third of the mixture over the crackers. Repeat cracker and caramel layers twice.
Immediately sprinkle chocolate chips over caramel; let stand 3-5 minutes or until glossy. Spread over top. Cover and refrigerate 2 hours or until chocolate is set. Using foil, lift layers out of pan; cut into 3x1-in. bars.