Create 2 Booleans (Initialized, Dialogue) … default both to false.
On click we check if the chest has been interacted with ( Initialized[true] ). If so, we check if the dialogue process has been completed ( Dialogue[true] )… if so, Do Inventory Stuff.
Otherwise, we set “Initialized” to true, Do some Dialogue stuff, Delay, then set “Dialogue” to true
The delay ensures that spam clicking has no effect (skipping dialogue). The delay value is for you to decide.
Your Button/interface should call an event in the Chest BP (represented by “R” in the above example).