Answer on another community:
The heart had a geis upon it - cast by Davy Jones
In a deleted scene from Pirates of the Caribbean: At World's End Davy Jones states to Governor Swann.
"Are you prepared for what comes after? When I carved that traitorous vessel from my body, I cast upon it a terrible geis. If you stab my heart, yours must take its place. The crew are not bound to me. They are bound to the Dutchman. And the Dutchman must have a captain. Will ye serve?"
from about 6:25 in
Basically, there are two curses, not just one. The first curse was placed by Tia Dalma (Calypso) on Davy Jones: to sail the seas, ferrying the dead souls for ten years, then come on shore to be with her for 1 day.
The second curse (or geis) was placed by Davy Jones himself when he cut his heart out: if someone stabs his heart, that person's heart must replace it.
So that's the answer to question 'Why did Will's heart have to be cut out as well?'. But as to why it had to be placed in the chest specifically, it most likely didn't have to. He could have kept it in a cloth sack and it would probably have still worked, since Davy Jones himself has had his heart in a chest, a cloth sack (when Norrington gave it to Beckett), a jar of dirt (Jack Sparrow) and even just transported in a shirt pocket (Jack and Norrington). But the chest was secure and safe, which is why it was used as the vessel in the first place.