TOKYO, Sept 17 (Reuters) - SoftBank Group’s Vision Fund has sold shares in South Korea’s major mail order firm Coupang for about $1.69 billion, the Nikkei financial daily reported on Friday, citing a U.S. regulatory filing. SoftBank sold 57 million Coupang shares at $29.685 each, the report said. Reporting by Tetsushi Kajimoto Editing by Chang-Ran Kim