Wash fresh blueberries under cool water. Pat them dry thoroughly with paper towels. Set aside on a plate.
In a large microwave-safe bowl, combine chocolate chips, peanut butter, and coconut oil. Microwave in 20-second bursts, stirring with a spatula after each burst until smooth (about 1 minute total). Do not overheat.
Add blueberries to the melted mixture. Gently fold with a spatula until evenly coated (be careful not to crush berries).
Pour powdered sugar into a large zip-top bag. Add coated blueberries. Seal bag and gently shake until berries are fully coated in sugar.
Spread coated blueberries in a single layer on a parchment-lined baking sheet. Refrigerate 30 minutes until coating sets.
Break apart any clusters and enjoy cold. Store leftovers in fridge.