* Nidec soars after expecting profit growth this FY
* Topix volume has fallen short for 3 days before big holiday
By Ayai Tomisawa
TOKYO, April 24 (Reuters) - Japan's Nikkei was flat in choppy trade on Wednesday as investors stayed cautious before earnings results, but it remained around a 4-1/2-month high as sentiment was supported by a rally in U.S. stocks.
Nissan Motor Co tumbled as much as 2.9 percent to 915.2 yen, the lowest since March 29, after TV Tokyo reported that it will announce a large cut to its earnings outlook for the fiscal year that ended in March due to weak sales in North America and China.
A Nissan spokesman declined to comment when contacted by Reuters.
The Nikkei share average dipped in and out of negative territory before ending the morning session little changed at 22,254.42 points.
In early trade, it hit as high as 22,362.92, the highest level since early December.
In U.S. markets, the S&P 500 index and the Nasdaq posted record closing highs after as a clutch of better-than-expected earnings reports eased concerns about a slowdown.
The broader Topix dropped 0.3 percent to 1,617.63.
Trading volume is expected to stay thin, with many investors on the sidelines before Japan's 10-day Golden Week holiday starting this weekend.
Volume on the mainboard has fallen short of 1 billion shares over the past three days.
With a flurry of earnings reports due out on Friday, investors are not taking large positions, analysts said.
"The market is bracing for weak earnings forecasts. But as earnings prospects seemed to be priced in already, big turbulence is not expected in the market," said Nobuhiko Kuramochi, a strategist at Mizuho Securities.
Nidec Corp surged 2.2 percent after the electric motor maker expected a 21.8 percent rise in its net profit for the year ending March 2020.
Profit-taking hit the utility sector, which rose on Tuesday, with Tokyo Electric Power tumbling 2.8 percent and Osaka Gas shedding 2.4 percent.
Editing by Kim Coghill