When you complete the side quest "Mixed Signals", you receive two new audio logs: "Satellite Signal: Repel Nightmare" and "Satellite Signal: Attract Nightmare". Use one of those from the menu ("repel" when you want to get rid of a Nightmare creature, "attract" when there is none) and the trophy is yours.
Beware, however, the logs have limited usage. You might want to reload the save afterwards.