As a combination of the prepositions de and chez, de chez simply means “from someone’s place” and is neither colloquial, neither formal.
Je reviens de chez mon frère.
I’m coming back from my brother’s place.
A little more colloquially, it can mean “from” in the meaning of a product coming from a company, a store, a restaurant, etc.
Ton lit, il vient de chez Ikea ?
Is your bed from Ikea?
T’as goûté le dernier burger de chez McDo ?
Did you try McDonald’s latest burger?
The most colloquial expression is “adjective + de chez + same adjective”. It basically means “extremely”, “completely”.
Mon dessin est raté de chez raté.
My drawing is a complete failure.
J’ai une question bête de chez bête…
I have a really stupid question…
This expression (e.g. bête de chez bête) probably originated because it can be understood as “stupid as if it were made by a specialist of stupid things, i.e. you can’t have something more stupid”.
Listen to the examples: