Combine cake mix, 1/3 cup evaporated milk and melted margarine. Spread half of mixture in bottom of 9 x 13" cake pan. Bake 5 minutes at 350~F. Heat the caramels and 1/3 cup evaporated milk until melted. On the baked layer, spread the pecans and chocolate chips and the melted caramels and milk mixture. Top with the other half of cake batter. Bake 20 minutes at 350~F.