The S&P 500 and the Nasdaq closed higher on Monday as shares of chipmaker Nvidia surged following a bullish note from Morgan Stanley, leading gains in other megacap growth stocks. Nvidia jumped 7.1%, its biggest single-day increase since May 25, when its 24% surge on a stellar revenue forecast pointed to the game-changing potential of artificial intelligence. The rally in the chipmaker's stock pushed the information technology index 1.85% higher, making it the strongest of 11 S&P 500 sector indexes. Other megacap growth stocks rose, including Alphabet , up 1.4% and Amazon.com, up 1.6%. Chipmaker Micron Technology ended with a...