Updates with closing prices

By Junko Fujita

TOKYO, July 16 (Reuters) - Japan's Nikkei share average ended flat on Wednesday, as concerns surrounding the elections to the upper house and the fate of trade negotiations with the United States overshadowed gains from chip-related shares.

The Nikkei .N225 inched 0.04% lower at 39,663.4. The broader Topix .TOPX fell 0.21% to 2,819.4.

"Investors have excuses for not buying or selling stocks," said Shigetoshi Kamada, general manager at the research department at Tachibana Securities.

"They are cautiously awaiting the outcome of the upper house election, while the outlook of the trade talks between is not clear even as the deadline approaches."

Opinion surveys suggest Prime Minister Shigeru Ishiba's coalition may lose its majority in the elections scheduled for July 20, forcing it to court an array of smaller parties pushing for easier fiscal and monetary policy.

Chip-related heavyweights Tokyo Electron 8035.T and Advantest 6857.T rose 1.75% and 0.64%, respectively, to track Nvidia's NVDA.O 4% gain overnight.

Nvidia unveiled plans to resume sales of its H20 AI chip to China, pushing the Nasdaq Composite .IXIC to end at another record high. .N

Toho 9602.T jumped 10.09% after the creator of the "Godzilla" movie franchise raised its annual net profit forecast.

Uniqlo-brand owner Fast Retailing 9983.T slipped 0.91% to weigh on the Nikkei the most.

Toyota Motor 7203.T lost 0.89% even as the yen fell to a more than three-month low against the dollar.

"Investors could not buy Toyota despite the yen's weakness because they are concerned about the tariff negotiations," said Kamada.

Local media reported Prime Minister Shigeru Ishiba is arranging to meet with U.S. Treasury Secretary Scott Bessent in Tokyo on Friday ahead of an August 1 deadline to strike a trade deal with the United States, else face punishing tariff of 25%.

(Reporting by Junko Fujita; Editing by Harikrishnan Nair)

((junko.fujita@thomsonreuters.com;))