No script is needed for this. You should do it like this.
Step 1: Place a chest, or any other container
Step 2: Go to properties and change the action ID from 0 to 2000. This means it's a quest
Step 3.1: Change the unique ID to anything between 1000-9999 (if I'm not mistaken).
Step 3.2: If you want a quest with multiple rewards where you have to choose between the items (e.g. inq, poi, wote etc.), use the same UNIQUE ID for the chests.
!
Be careful, if you accidently use the same unique on two different quests, you can only take one of the two (if you accidently use unique ID 3000 for soft boots and the same ID for the demon helmet on another quest, you cannot take both).