Nvidia investors are getting excited about another AI giant.Nvidia (NVDA 0.37%) stock just hit new all-time highs. But there's a catch: Nvidia's latest rise has nothing to do with the company itself, at least not directly. Instead, there's another AI stock that is causing the entire industry to rise in valuation.News from Oracle is fueling Nvidia's stock priceAmazingly, no company with a market cap north of $500 billion has ever seen its stock price rise by more than 30% in a single trading day. But that's ...