Heat oven to 180ºC . Grease foil-lined 13 X 23 cm baking pan.
Microwave chocolate squares and butter on high 2 minutes or until butter is melted. Stir until chocolate is completely melted. Stir sugar into chocolate until well blended. Mix in eggs. Stir in flour. Spread half of batter in prepared pan.
Bake 25 minutes, or until batter is firm to the touch.
Meanwhile, microwave caramels and cream on high 3 minutes or until caramels begin to melt. Whisk until smooth. Stir in 1 cup nuts. Gently spread caramel mixture over brownie batter in pan. Sprinkle with chocolate chips, if desired. Pour remaining unbaked brownie batter evenly over caramel mixture; sprinkle with remaining nuts (some caramel mixture may peak through).
Bake additional 30 minutes. Cool in pan. Run knife around edge of pan to loosen brownies from sides. Lift from pan using foil as handle. Cut into 24 pieces.