Preheat oven to 350°.
Melt caramels with ft cup milk in medium saucepan over low heat, stirring until smooth.
Mix together remaining milk, cake mix and margarine in large bowl.
Press half of cake mixture onto bottom of ungreased 13 x 9-inch baking pan.
Bake 8 minutes.
Sprinkle chocolate chips and 1 cup walnuts over crust; top with caramel mixture, spreading to edges of pan.
Top with teaspoonfuls of remaining cake mixture; press gently into caramel mixture.
Sprinkle with remaining walnuts.
Bake 16 to 18 minutes.
Cut into bars.
Approximately 2 dozen