Footage of the incident circulating on social media shows intruders wearing hoods and masks darting between aisles while staff look on.
They knock over display cases and tear down shelves, grabbing anything they can.
They jumped over broken glass and fled with their arms filled with expensive goods into waiting getaway cars, including a BMW and a Lexus.
Spate of raids
It follows a spate of similar raids in Los Angeles and other major US cities.
Republican politicians have blamed soft-on-crime policies in Democrat-controlled areas for a rise in crime.
The LAPD said its officers responded to calls of “numerous persons shoplifting” at Westfield Topanga Mall aboutr 4pm on Saturday.
A spokesman said its officers “were on the scene quickly and have several investigative leads”.
Police estimated the loss from the smash-and-grab raid was $60,000 to $100,000.
The same Nordstrom store was hit two years ago by a group of five masked robbers who pepper-sprayed a member of staff and made off with about $25,000 of goods.
‘Absolutely unacceptable’
Karen Bass, the Democrat mayor of Los Angeles, called the robbery “absolutely unacceptable” and vowed the perpetrators would be “held accountable”.
She said: “The Los Angeles Police Department will continue to work to not only find those responsible for this incident, but to prevent these attacks on retailers from happening in the future.”
Just days earlier, another flash-mob-style robbery took place at an Yves Saint Laurent store in Glendale near Los Angeles.
The thieves stole about US$300,000 of goods, according to the local NBC News network.
Starbucks has already closed six of its branches in Los Angeles amid safety fears. They include two spots near Hollywood Boulevard and another near Santa Monica Boulevard.
The coffee shop chain said issues with chronic homelessness, vandalism and theft were driving factors for the closures.
