In a large bowl, combine dry cake mix, pecans, ⅓ cup evaporated milk and melted butter.
Press half of the batter into the bottom of a greased 13-by-9-by-2-inch glass baking dish. Bake in preheated 350-degree oven for 8 minutes.
Meanwhile in the top of a double boiler over simmering water, melt caramels with remaining ½ cup evaporated milk. When well mixed, pour over baked layer. Cover with chocolate morsels.
Spread remaining batter on top of morsels. Return to oven and bake 18 minutes. Let cool and cut into squares.