When you place a chest it usually needs to have contact with the ground and not collide with the terrain. However, it might be desirable for a chest to look like it has been half-buried, while still allowing players to do things that they could usually do with chests, like breaking them open.
Although that is a nice example @stelagel I do believe the OP was looking to sink them into the ground, not into foundations and or ceiling tiles. Like a chest half buried in sand sort of thing.
I think they mean a cosmetic chest that appears to be buried in the dirt. Kinda like a pirate chest maybe? I’m thinking a skin that appears it is buried.