Line baking sheets with parchment paper or wax paper. Add the salted and unsalted peanuts to the slow cooker, then layer the broken almond bark, semi-sweet chocolate chips, and milk chocolate chips over the top without stirring.

Cover the slow cooker and cook on LOW for about 1 hour. Keep the lid in place to retain heat, but check the mixture around the one-hour mark because slow cookers can vary.

Stir thoroughly, scraping around the sides and bottom so the melting coatings combine with the peanuts. Continue cooking on LOW for another 30 to 60 minutes, stirring occasionally, until the coating is smooth and fully melted.

Use a tablespoon or small cookie scoop to drop portions onto the prepared parchment. Leave a little space between each cluster so the pieces remain separate as they cool.

Let the clusters cool and set completely at room temperature for 30 to 60 minutes, or refrigerate them for about 20 to 30 minutes. Transfer the firm candy to an airtight container for storage.