Microwave butter in a large bowl until melted. Stir in the peanut butter and Nutella and mix until smooth. Add in the powdered sugar and mix until combined. Fold in the Rice Krispies and stir until just combined.
Line a cookie sheet with parchment paper or a baking mat. Using a cookie scoop and damp hands, roll the mixture into about 42 evenly-sized balls and place on cookie sheet. Refrigerate for 15 minutes.
Place the chocolate chips in a small bowl and microwave until completely melted, stopping to stir in 15 second intervals. This should take about 90 seconds total. Use a fork to drizzle the chocolate over the truffle balls or dip the top half of the balls into the chocolate. Top with sprinkles if desired. Let harden completely before serving.
Video
Notes
Store in an airtight container in the refrigerator for up to a week.