Line a standard muffin pan with 12 paper liners and set aside.
In a medium microwave-safe bowl, melt the milk chocolate chips by heating for 1 minute, stirring, and then continuing in 30-second intervals until fully smooth.
Spoon 1 teaspoon of the melted chocolate into each liner and spread to cover the base evenly. Transfer the pan to the refrigerator to chill.
In a separate small microwave-safe bowl, combine caramel bits with water. Microwave for 1 minute, stir, and continue heating in 20-second increments until the mixture is fully melted and smooth.
Fold the chopped peanuts into the caramel mixture and set aside.
In a small mixing bowl, thoroughly blend the peanut butter and powdered sugar. Keep aside.
Retrieve the muffin pan from the refrigerator.
Portion 2 teaspoons of the peanut butter mixture into each chocolate base, spreading evenly.
Add 1 tablespoon of the caramel-peanut mixture atop the peanut butter layer.
Finish with another 2 teaspoons of the melted chocolate over the caramel layer, smoothing the top.
Refrigerate until the chocolate layer is completely firm.