King Wangchuck took a two-hour tour and listened as Jay Puri, Nvidia's head of global business, discussed how Bhutanese investment in data centers and Nvidia chips could combine with the kingdom's biggest natural resource, hydropower, to create new AI systems. But in Washington, officials worry that Nvidia's global sales spree could empower adversaries. Now the Biden administration is working on rules that would tighten control over AI chip sales and turn them into a diplomatic tool.