Key PointsChip stocks are losing ground today, and Sandisk is participating in the pullback. Investors are showing signs of nervousness ahead of SpaceX's upcoming IPO. 10 stocks we like better than Sandisk › Sandisk (NASDAQ: SNDK) stock is in the red in Tuesday's trading despite having initially posted big gains. As of 12:30 p.m. ET, the company's share price was down 3.5%. Meanwhile, the S&P 500 was off 1.6%, and the Nasdaq Composite was down 3…