After removing pan from oven, immediately spoon caramel mixture over brownie; sprinkle with remaining nut mixture. Return to oven and bake an additional 7 to 10 minutes or until caramel is bubbly around edge of brownie. Cool completely on cooling rack, about 2 hours. Before cutting, run knife around edge of pan to loosen. Cut into 4 rows by 4 rows. Store covered at room temperature.