You can still get a chance to loot legendary crafting reagents and BoA gear tokens plus guaranteed junk from those chests even after you looted them 5 times a day.

Tested in the area under main base (Kroke area), they respawn here at one of random points every 15-20 mins after looting (there's one point in the cave that I think is not displayed in addon). So far you can endlessly loot them...