It's a common phrase used to:
* Invite someone to your home: "Venez chez moi pour dîner" (Come to my place for dinner).
* Ask about someone's living situation: "Où est chez vous?" (Where do you live?).
* Refer to someone's home in general: "J'ai passé une agréable soirée chez vous" (I had a pleasant evening at your place).
The phrase "chez vous" is always used in a polite and respectful way. It's a way of acknowledging that someone has a home and a place to belong.