Heat oven to 350. Line 16 muffin cups with foil or paper baking cups. Melt butter in medium saucepan over low heat. Remove from heat; stir in brown sugar. Add vanilla and egg;mix well. Add flour,baking powder and salt; blend well. Stir in 1/2 cup chopped nuts. Divide batter evenly into lined muffin cups. Bake at 350 for 16 to 20 minutes or until golden brown.
Meanwhile, in small saucepan over low heat, melt caramels with water;stir constantly until smooth.* Immediately after pans are removed from oven, place chocolate chips evenly into middle of each brownie. Spoon 1 scant tbsp of caramel over chocolate chips in each cup. If necessary, stir additional water into melted caramels to maintain spoonable consistency. Sprinkle 1/4 cup finely chopped nuts evenly over brownies. Cool completely. Store in tightly covered container.
*TIP*: To melt caramels in microwave, place in small microwave safe bowl with 1 tbsp water. Microwave on HIGH for 2 to 3 minutes, stirring occasionally.