A sign is posted in front of the Nvidia headquarters on May 10, 2018 in Santa Clara, California.Justin Sullivan | Getty ImagesSeveral Chinese electric carmakers are turning to U.S. chip giant Nvidia to power their semi-autonomous driving systems, as they ramp up competition with Tesla in the world's largest car market.Chinese start-ups Xpeng and Nio are using the Nvidia Drive Orin chip in their latest cars. Baidu, which last year launched an auto unit called Jidu, announced plans to use the same Nvidia chip in its upcoming car, as well as Polestar, a brand under Chinese auto giant Geely.With this…