Put the chocolate and butter in a pan. Add the corn syrup using a tablespoon measurer that has been heated (so that it goes into the pan more easily). Heat the pan until everything is melted together. Turn off and stir in the corn flake cereal. (Try to do it gently so that you don't break too many of the flakes--they add to the texture of the finished product if most of them are whole.) Fill the baking cups and press their middles in with a teaspoon. Put your eggs in, and then chill to let set. Keep chilled until ready to serve.
NOTE: Around Easter there are often malted candy eggs made to look something like real bird eggs. These are perfect! Also, you can vary the size of your nests to your heart's content; if you wanted to spread the entire recipe onto a paper plate and make a large nest to hold a different Easter/spring surprise, go for it!