Preheat oven to 350°F. Combine cake mix and nuts in large bowl. Stir in butter and 2/3 cup evaporated milk. Spread half of batter into greased 13×9-inch baking pan.

Bake for 15 minutes. Heat caramels and remaining evaporated milk in small saucepan over low heat, stirring constantly, until caramels are melted. Sprinkle morsels over brownie; drizzle with caramel mixture.

Drop remaining batter by heaping teaspoonfuls over caramel mixture. Bake for 25-30 minutes or until center is set. Cool in pan on wire rack.