Heat oven to 350°F. Spray with nonstick cooking spray or grease bottom only of 13x9-inch pan. In large bowl, combine brownie mixes, chocolate pouches from mixes, oil, water and eggs; beat 50 strokes with spoon. Pour about half of batter into sprayed pan.
In large saucepan, combine condensed milk, peanut butter chips and peanut butter; cook over low heat for 5 minutes or until chips and peanut butter are melted, stirring constantly. Spoon and spread peanut butter mixture over batter. Drop remaining half of batter over peanut butter layer. Sprinkle with chopped peanuts.
Bake at 350°F. for 35 to 40 minutes or until edges begin to pull away from sides of pan. DO NOT OVERBAKE. Cool 2 hours. Refrigerate 1 1/2 hours or until completely cooled before serving. Cut into bars.