How to destroy Fortnite Chrome structures ? 

Doing this can be a bit difficult. But completing this challenge will reward you 20k XP, which will help to unlock more skins for Battle Pass

Chrome formations can be found in new locations on the map such as Shimmering Shrine, Lustus Lagoon, and Herald's Sanctum

You actually have to use Chrome Splash on objects or structures around you to complete this challenge. 

In Fortnite, Chrome Splash can be found in chests and on-the-ground loot. However, we recommend you to go to the eastern parts of the map as Chrome items are easy to find and destroy there. 

Gather as much chrome splash as possible before moving on to a non-chromed structure. You may also have to go somewhere else, such as the corner crossroads

Splash chrome on everything you see as you enter the building. Now, smash whatever you can, including barrels, walls, and chests. 

Still, having trouble? then Simply go to a multi-story building and splash Chrome as much as you, Then break the foundation of that building to bring it down. All this will be counted in the challenge.