Took me awhile to figure out why this wouldn't unlock but I have now managed to get this achievement to pop.
This must be done on the Storyline ZEKE battle. You need to have Radome (earned from the Chyrsalis) on ZEKE. This makes him immune to chaff.
When the fight starts throw a chaff and Paz will say, "What are you trying to do?"
The achievement will then unlock.