Nio's sales are rising, it posted a strong second quarter, and two new brands could shift the company into a higher gear.If you've been along for the Nio (NIO -7.21%) investment ride since the beginning, it hasn't been for the faint of heart. There have been wild ups and downs, bankruptcy rumors, and capital raises. Despite all the twists and turns, it was easy to buy into the early hype, especially considering China's electric vehicle (EV) market is years ahead of the United States' and Nio's luxury vehicl ...