In a large mixing bowl beat powdered sugar, peanut butter, butter, and vanilla with an electric mixer until combined and smooth. Shape dough into 1-inch balls. Transfer balls to a waxed-paper-lined cookie sheet. Cover with waxed paper and chill until firm, about 1 hour.
Place candy melts in a medium microwave-safe bowl. Microwave on high for 1 minute or until melted and smooth, stirring twice. Use a fork to dip chilled peanut butter balls, one at a time, into melted chocolate to coat, allowing excess to drip off into bowl. Place on waxed paper-lined cookie sheets. Immediately top with sprinkles before chocolate sets.