Fortnite Chapter 2 Season 2 introduced a new type of chest. These large chests can be found in new locations such as the Rig, Shark, and Agency Headquarters. They can also be found in secret bases hidden in the game, like the one in Pleasant Park.
Chests should scan you, but will simply tell you that they cannot open and are for henchmen only. The good news is that chests are dumb and you can easily cheat them. The first method is to dress up using a phone booth. Phone booths can be found in the new locations, and entering them will allow you to dress like minions. You can then go into the chest and trick them into opening them for you.
The second method is even simpler. If you can't find a phone booth, look for the minions. Shoot them and they will be shot instead of dying right away. Run towards the downed enemy and you will have two options, you can either give them a shakedown or wear them. Select the option to carry them, then bring them to the chest you want to open.
Interact with the chest again and you'll hold them in front of you, the chest will scan them and you can get the right loot inside. If you are wondering if chests are worth it, the answer is yes. They contain a lot more loot than the standard chests you'll find in the game, often dropping multiple weapons with high rarities, healing and shield items, and also granting you plenty of XP.
We have lots of other helpful guides that you may find useful. How to get Deadpool, where to find Deadpool's letter to Epic Games, how to deal damage to henchmen, and how to customize your new Maya skin which you can get with the Battle Pass.
