Demand in China has begun surging for a business that, in theory, shouldn't exist: the repair of advanced Nvidia artificial intelligence chipsets that the U.S. has banned the export of to its trade and tech rival.

Nvidia Corp. and Advanced Micro Devices Inc. plan to resume sales of some AI chips in China after securing Washington’s assurances that such shipments would get approved, a dramatic reversal from the Trump administration’s earlier stance on measures designed to limit Beijing’s AI ambitions.