TOKYO, Aug 25 (Reuters) - Japanese stocks slumped about 2% on Friday, as chip-related heavyweights Advantest and Tokyo Electron dropped after U.S.-listed shares of tech darling Nvidia ended flat overnight despite a robust outlook and record quarterly revenue.

The Nikkei was down 1.92% at 31,666.36 by the midday break, after falling as much as 2% earlier in the session. The index is set to lose 0.69% for the week.

The broader Topix fell 0.88% to 2,266.44 and is poised to drop 1.31% for the week.

Shares of Nvidia ended flat at $471.63 the day after the company beat analyst expectations when it reported second-quarter revenue of $13.51 billion after the bell, and predicted revenue would reach $16 billion in the third quarter.

The three major U.S. stock indexes ended down more than 1% each overnight, led by a drop in the Nasdaq after this week's sharp gains and as investors were cautious ahead of Federal Reserve Chair Jerome Powell's speech in Jackson Hole on Friday.

"Japanese market tracked Wall Street's declines. Foreign investors seemed to have lost their appetite for Japanese equities today," said Shigetoshi Kamada, general manager at the research department at Tachibana Securities.

"Investors were bracing for market declines after (Fed Chair Jerome) Powell's speech later in the day. It appears like his message will be hawkish."

Investors await Powell's speech for clues on the U.S. central bank's monetary policy.

Shares of Japanese chip-testing equipment maker fell, with Advantest tanking nearly 10% while chipmaking equipment maker Tokyo Electron slipped 5.61% and its peer Screen Holdings lost 3.51%.

Technology investor SoftBank Group fell 3.79%.

Of the 33 industry sub-indexes on the Tokyo Stock Exchange, only three rose, with the shipping sector gaining 0.24%.

The services sector was trading flat, while the operator of Tokyo Disney Resort Oriental Land advanced 0.71%.

(Reporting by Junko Fujita; Editing by Sherry Jacob-Phillips)