No? Ok then.

Erm....

Set it so that it starts when hero touches, have the chest pic for the pic:

Move pic: (move it however much to open it, just fiddle with the move event in the event menu, try move 180 degree for this event)
Change Items: Add potion
Message: You recieved ____ potions
Erase Event

Have the pic of open chest (tileset uploading commencing soon) under the event show it show open chest when event fin.

That's more or less the things you need to choose in the evnt menu, and in that order.

Can Bluecube clarify me in this please? There is no call event so...