HEAT oven to 350° F. Grease foil-lined 13 x 9 inch baking pan.
MICROWAVE chocolate squares and butter in microwavable bowl 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 1/2 of batter in prepared pan.
BAKE 12 minutes or until batter is firm to the touch.
MEANWHILE microwave caramels and cream in microwavable bowl on HIGH for 3 minutes or until caramels begin to melt.
Whisk until smooth.
Stir in 1 cup of 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 leak through.)
BAKE additional 20 minutes.
Cool in pan.
Run knife around edge of pan to loosen brownies from sides.
Lift from pan using foil as handles.
Cut into 24 fudgy brownies.