In a large saucepan, melt chocolate and butterscotch chips with peanut butter over low heat. Spread half in a greased 15x10x1-in. pan; chill until firm. Stir in peanuts into remaining melted mixture and set aside. Place sugar and vanilla or maple flavoring in a large bowl; set aside. In a small saucepan, combine butter, milk and pudding mix; bring to a boil and boil for 1 minute. Add to bowl and beat until smooth; spread over chilled layer in pan. Chill until firm. Cover with reserved peanut/chocolate mixture. Refrigerate until serving. Cut into bars.