1. Preheat oven to 350°F
2. Melt 1 cup chunks and butter in large, heavy-duty saucepan over low heat, stirring constantly, until smooth. Remove from heat; stir in eggs. Add flour, sugar, vanilla extract and baking soda; stir well.
3. Spread batter into prepared baking pan; sprinkle with remaininig chunks and nuts.
4. Bake for 20-25 minutes or until wooden pick inserted in center comes slightly sticky.
5. Microwave caramels and milk in small, microwave-safe bowl on high (100%) power for 1 minute; stir. Microwave at additional 10-20 second intervals; stir until smooth. Drizzle over warm brownies. Cool in pan on wire rack.