Nvidia’s new chip is a response to the Biden administration’s new rules restricting exports of American chip technology to China. HONG KONG— Nvidia Corp. has begun offering an alternative to a high-end chip hit with U.S. export restrictions to customers in China, after the new rules threatened to cost the American company hundreds of millions of dollars in lost revenue. Nvidia said the new graphics-processing chip, branded the A800, meets U.S. restrictions on chips that can be exported to China under new rules rolled out last month. The chip went into production in the third quarter, the company said.