(Reuters) - CoreWeave has signed a $6.3 billion initial order with backer Nvidia, the data center operator said on Monday, in a deal that guarantees that the AI chipmaker will purchase any cloud capacity not sold to customers. Shares of CoreWeave rose 8% as the deal cements the company's position as a key Nvidia cloud partner and cushions it against any potential decline in demand for AI computing capacity. CoreWeave operates AI data centers in the U.S. and Europe, offering access to Nvidia's GPUs, which ...