IonQ, Opendoor, and DigitalOcean could soar higher over the next few years.Many investors look toward the tech sector for potential millionaire-maker stocks. But for every stock like Nvidia which minted new millionaires, there are plenty of stocks like Intel which shriveled over the past decade.So if you're looking for the next Nvidia and trying to avoid the next Intel, you should look for companies that are establishing an early mover's advantage in their nascent markets, growing rapidly, widening their mo ...