C2 accept only one triggered condition per event because of how events work.
The event sheet is read top to bottom each execution tick.
As such, the order of the event has an impact on the program's logic.
Triggered conditions are a bit of an exception as they are "triggered" at a different time then when the event is read/encountered.
In your case, what you want is to add a second sprite to your chest, a bigger that acts as an "area of effect" and use the "is overlapping" condition.
When your character is overlapping the range of a chest AND your player presses the action key (so one triggered event), then the chest is opened.
That could give you something like this example capx.
For random drops, I made this tutorial a while ago that could answer your new question.