Line a 9x13 pan with aluminum foil and spray with non-stick cooking spray.
Melt chocolate chips and peanut butter over a double boiler or in the microwave on 50% power. If using the microwave, cook for 1 minute then stir. Continue cooking in 30 second increments until chocolate is melted.
Pour mixture into the pan and spread out evenly. Place pan in the refrigerator for 20 minutes.
While Layer 1 is chilling, begin making Layer 2.
Melt butter in a medium sized pot over medium heat.
Add in milk and sugar, stirring until the sugar has dissolved.Bring to a boil and let cook for 5 minutes, stirring occasionally.
Add marshmallow fluff, peanut butter and vanilla and stir until smooth.
Remove pot from heat and fold in peanuts.
Spread the nougat filling on top of the chocolate layer.
Allow to cool completely.
While Layer 2 is cooling, place caramels and whipped cream in medium pot.
Cook over low heat for about 10-15 minutes (or until smooth), stirring occasionally.
Pour over nougat layer and allow to cool completely.
For Layer 4, melt chocolate chips and peanut butter over a double boiler or in the microwave on 50% power. If using the microwave, cook for 1 minute then stir. Continue cooking in 30 second increments until chocolate is melted.
Pour chocolate mixture evenly over the cooled caramel layer and spread to cover the entire layer.
Place pan in refrigerator for at least 1-2 hours or until all layers have cooled and firmed up.
Lift the foil sling out of the pan and slowly peel the foil away.