I noticed in LootManager.cpp that I can set [event] loot=currency, but I can't seem to write an event that makes treasure chests spawn currency propwerly.  Sadly, I also can't find any examples in the FLARE mods/*/maps/*.txt files, either.  

For instance, the following just seems to spawn an empty chest in repeated runs (cavern.txt of polymorphable):

[event]

location=94,62,1,1

type=run_once

hotspot=-16,-16,32,32

tooltip=Chest

loot=currency,94,63

mapmod=object,94,62,206