It more than doubled its sales. It unveiled a new line of microchips. It promised to keep rolling out new products for the next few years. In the end, Nvidia, the chip manufacturer, delivered the kind of blockbuster results that traders and investors had been waiting for. Yesterday’s ‘Nvidia Day’ (as the company’s quarterly results days are now known on Wall Street) turned out to be better than even the most bullish investor could have hoped for.