Pour the popped corn onto 2 baking sheets lined with a silpat or parchment paper. Remove any unpopped kernels. Mix in marshmallows, Robin Eggs, and nuts.
In a microwave-safe bowl, melt white candy melts on 50% power. Drizzle melted evenly over the popcorn. Using a spatula, toss the popcorn mixture to coat it with melted candy.
Put colored candy melts in three Ziploc bags, microwave candy melts at 50% power for 1 minute. Knead candy in the bag. Continue to microwave and knead at 30-second intervals until smooth and completely melted.
Snip off a small corner of the Ziploc bags and drizzle the melted candy on top of the popcorn.
Let the popcorn rest on the baking sheets until the melted candy is dry.
Notes
*About 8 cups of popped popcorn if you want to sub already popped popcorn