In the past 12 months, the fairy tale for Nvidia stock has just kept going. Nvidia has more than doubled in the past year.$NVIDIA Corp(NVDA)$ stock is now up nearly 1,300% in the past five years and 8,200% in the past 10 years. But investors should understand just how expensive the stock is at current levels. $NVIDIA Corp(NVDA)$ stock isn’t as much of a no-brainer buy as it may seem at first glance. $NVIDIA Corp(NVDA)$