Line a baking sheet with wax paper, parchment paper, or a silicone liner. This will give you a flat surface to lay each buckeye pretzel bite on.
In a medium bowl, mix together the 1 cup peanut butter and 2 Tbsp butter until smooth.
Add to the peanut butter mixture, the ½ cup powdered and ¾ cup brown sugars and mix until combined. As needed, add more powdered sugar until mixture is easy to handle. It should be moist, but not overly stick to your fingers.
Using about 1 tsp – 1 Tbsp of peanut butter mixture, sandwich between two pretzels and remove any excess. Place on the lined baking sheet and repeat for remaining buckeye pretzel bites.
Optional: Refrigerate buckeye bites for 30 minutes or freeze for 15 minutes. This will help keep them together when dipping in chocolate.
Add the 2 cups chocolate chips to a microwave safe bowl. Microwave in 30 second increments, stirring between each zap. (Optional) If melted chocolate is too thick, add vegetable shortening or coconut oil to taste to thin the chocolate.
Dip each sandwich in the chocolate, then return to the baking sheet and wait 30-90 minutes for the chocolate to set. Store in an airtight container.