Mix the peanut butter, protein powder, honey and vanilla together until smooth. Add the Rice Chex and smash with a spoon, stirring and smashing until most of the cereal is broken and everything is mixed well.
Use a cookie scoop to scoop out tablespoonfuls of the mixture and roll them between your hands to form balls. Sprinkle a little powdered sugar on top if desired.
Place the chocolate chips in a small glass bowl and microwave for 45 seconds. Stir and then microwave for another 30 seconds. Stir until smooth. If the chocolate isn't fully melted, microwave for another 15 seconds and then continue stirring. Place the melted chocolate in a small ziplock bag and snip a tiny hole in the corner. Squeeze the chocolate out as a drizzle over each cookie ball. Eat immediately, or store in the refrigerator or store at room temperature until ready to eat.