I actually use something like that in my campaign.
Just create a custom destructible (like a barrel), with a custom chest model (one with an open animation).
And then you need a trigger that performs a couple of actions whenever one of those chests is destroyed; revive destroyed destructible with 1 hp, make it invulnerable, play its ''open'' animation (or ''death alternate'', depends on the model), and create an item at the chest.