* Metal shares stage rally
* Toshiba up on report of possible chip unit sale talks
By Ayai Tomisawa
TOKYO, Aug 23 (Reuters) - Japan's Nikkei share average rebounded on Wednesday morning after Wall Street gained as U.S. lawmakers' comments on tax reform and the debt ceiling boosted investor appetite.
The Nikkei rose 0.7 percent to 19,509.48 in midmorning trade, after falling for the fifth day on Tuesday to mark its longest losing streak since April 2016.
In the U.S., the Dow rose 0.9 percent, the S&P 500 climbed 1 percent and the Nasdaq gained 1.4 percent, posting their best one-day percentage gains in over a week, while the dollar stood tall as investors awaited the annual Jackson Hole conference later this week.
In the U.S., House Speaker Paul Ryan told CNN at a town hall on Monday that tax reform would be easier to pass than the failed healthcare overhaul because Republicans have built a consensus.
Separately, Senate Majority Leader Mitch McConnell said on Monday that there was "zero chance" that the United States will fail to raise the debt ceiling in September, allaying concerns that the country is poised to default on its debt, according to media reports.
Over the past week, the Japanese market was rattled by geopolitical tensions between the United States and North Korea, while the United States and South Korea began joint computer-simulated military exercises on Monday.
"As long as Trump doesn't say something provocative, the market should stay calm for now," said Kazuhiro Takahashi, an equity strategist at Daiwa Securities, adding that investors are picking up recently battered stocks on bargain hunting such as electronics shares and automakers.
Sony Corp gained 1.3 percent, Hitachi Ltd added 0.9 percent and Toyota Motor Corp rose 1.0 percent.
Metals prices, including copper, zinc and nickel, ended higher, lifting metal stocks. Pacific Metals jumped 2.9 percent, Dowa Holdings surged 1.7 percent, while Sumitomo Metal Mining soared 2.3 percent.
Meanwhile, Toshiba Corp jumped 4.6 percent on a media report that the company is prioritising talks with Western Digital on the sale of its chip unit.
The broader Topix rose 0.5 percent to 1,603.24. (Editing by Michael Perry)