Melt milk chocolate chips, butterscotch chips and peanut butter in a pan over low heat; stirring constantly. Pour mixture into a 9 x 13″ baking pan lightly coated with nonstick spray or lined with plastic wrap which is long enough to drape over sides of the pan. Spread mixture and place in the refrigerator for 30 minutes.
FOR THE NOUGAT LAYER:
Melt butter over medium heat in pan; add sugars and evaporated milk; bring to a boil, and cook additional 5 minutes while stirring. Remove from the heat and add marshmallow creme and peanut butter. Pour over the bottom layer and gently spread mixture. If you use peanuts, scatter across the top. Place in the refrigerator for 15 – 30 minutes.
FOR THE CARAMEL LAYER:
Place the unwrapped caramel candy, butter, and cream in a medium saucepan. Place over low heat and stir until the mixture has completely melted and is smooth. Pour in the pan and quickly spread over nougat layer. Place in the refrigerator for 15 – 30 minutes.
FOR THE TOP CHOCOLATE LAYER:
Melt milk chocolate chips, butterscotch chips, and peanut butter in a pan over low heat, stirring consistently. Pour over the caramel layer and spread.
Sprinkle chopped nuts over top of chocolate while still soft.
Place in the refrigerator for at least 1 hour before cutting into squares. These are very rich, cut into small squares. If eating right away, place on platter and serve. If the bars start to get too soft, place in refrigerator to firm up a bit.