In a food processor, add Oreos and pulse until smooth crumbs. Set aside.
In a small bowl, combine 1/2 the chocolate chips (6oz) and 1/4 cup milk.
Microwave until chips are melted, stirring until smooth. Set aside to cool.
Spread 1/3 crushed Oreos on bottom of a 9x13 pan. Press down with fork to create even layer.
Peanut Butter Layer: Place 8 oz cream cheese in medium bowl. Beat with mixer until smooth. Sprinkle in the vanilla pudding mix and peanut butter. Combine until smooth. Slowly add in 1 3/4 cups of milk and use mixer to combine. Spread mixture over Oreo crumb layer.
Spread additional 1/3 mixture of Oreo crumbs on top of peanut butter layer.
Chocolate Layer: Place remaining 8 oz cream cheese in medium bowl. Beat with mixer until smooth. Sprinkle in the chocolate pudding mix, cooled chocolate sauce from step 2, and 1 1/2 cups milk. Beat until smooth. Spread over Oreo crumb layer.
Spread last 1/3 Oreo mixture over chocolate layer.
Spread whipped topping evenly on top of the Oreo layer.
Sprinkle chocolate chips, shaved chocolate, peanuts, etc on top of dessert for garnish (optional)
Place pan in refrigerator and allow to chill 4-6 hours. Serve and enjoy!