Growth may mellow out, but the long-term prospects remain strong.Nvidia (NVDA +0.81%) has a strong case for being the most discussed stock in recent years. It has also been one of the best-performing, up more than 960% in the past three years.Considering how much the stock has skyrocketed, investors may think Nvidia's best days are behind it. Luckily, there's one key reason why that might not be the case. It's true that Nvidia is beginning to face additional pressure as companies like Alphabet and Amazon be ...