SAN FRANCISCO, March 13 : When Jensen Huang strides onto the stage of a packed hockey arena to kick off Nvidia's annual developer conference on Monday, he is likely to reveal products and partnerships geared toward keeping the AI chipmaker atop a growing array of competitors. Taking over the heart of Silicon Valley for most of a week, Nvidia GTC, as the conference is known, has become CEO Huang's preferred event to show off Nvidia's AI advances in chips, data centers, its chip programming