Mix peanut butter and butter together in a mixing bowl. Gradually stir in powdered sugar until combined well into a dough ball. If needed, add more powdered sugar a little at a time until mixture holds together in a large ball. Cover and let peanut butter dough sit for about 15 minutes to firm up, or cover tightly with plastic wrap and refrigerate until ready to form balls.
Shape into 1-inch balls, place on a baking sheet, cover and refrigerate for at least 20 minutes to allow to firm up. Dough balls should hold shape before dipping in chocolate. Add more refrigeration time if necessary.
Melt chocolate according to package instructions.
Dip peanut butter balls one at a time into melted chocolate, allowing excess to drip off. Place on waxed paper lined baking sheet, cover and refrigerate until ready to serve.