Prepare two baking sheets with wax or parchment paper. Set aside.
In a large bowl, mix together chocolate chips, 1 cup of peanut butter chips, 7 tablespoons of butter, and peanut butter.
Microwave on low power for 1-2 minutes, stirring every 20 seconds, until smooth (be careful not to scorch the chocolate!) You could also put everything in a small saucepan over low heat, stirring constantly until melted.
Add pretzels and peanuts to the melted chocolate mixture and gently toss to combine.
Drop spoonfuls of mixture onto prepared baking sheets. Refrigerate for 30 minutes, or until chocolate has set.
Add remaining 1 tablespoon of butter and remaining peanut butter chips to a bowl and microwave, as before, until melted.
Pour the melted mixture into a ziplock bag and cut the corner off. Drizzle over refrigerated clusters. Enjoy! Store leftovers in the fridge.