Place almond bark in a slow cooker. Stir occasionally on High until mostly melted, about 2 minutes. Reduce heat to Low. Stir in chocolate chips until mixture is completely dark, about 30 seconds. Add peanuts.
Drop a spoonful of the peanut clusters onto a parchment paper-lined countertop to test if they are thick and chunky. Mix in more peanuts and chocolate chips if the mixture is too loose and runny.
Line 4 to 5 baking sheets with parchment paper. Lay spoonfuls of the peanut clusters on top using a melon baller. Allow to harden, about 1 hour.