Used to describe when someone over uses something that belongs to someone else. Usually it is in reference to drugs or alcohol.
Marcus: You bring the smoke, bra?
DeRon: Hell yeah I brought the smoke, but don’t tell Ray-Ray.
Marcus: Fo sho. That nigga be chiefin’ everybody’s shit.
The word “chiefin’” historically refers to Native American chiefs. One of the privileges of being chief was they had free access to the entire tribe’s possessions. The modern day version used in Washington DC has a very similar meaning. It means someone is hogging all of someone else’s booze or drugs.
The song “14,400 Minutes” by Chance the Rapper uses this term in its proper context: