Chip designer Nvidia said that US officials told it to stop exporting two top computing chips for artificial intelligence work to China, a move that could cripple Chinese firms’ ability to carry out advanced work like image recognition. The company on Wednesday said the ban, which affects its A100 and H100 chips designed to speed up machine learning tasks, could interfere with completion of developing the H100, the flagship chip Nvidia announced this year. The announcement signals a major escalation of the US crackdown on China’s technological capabilities as tensions bubble over the fate of Taiwan, where chips for Nvidia and almost every other major chip firm are manufactured. The US department of Commerce would not say what new criteria it has laid out for AI chips that can no longer be shipped to China. . . .