One analyst sees Nio shares jumping nearly 50% from here.Shares of Chinese electric vehicle (EV) maker Nio (NIO 10.96%) have been flying recently. Nio's American depositary shares were up by 11.1% as of 3:50 p.m. ET today. That brings its five-day surge to a whopping 38%.That move was initiated by Nio's promising second-quarter earnings report last week. And the positive momentum continued today after the company caught an upgrade from one Wall Street analyst and a very bullish label from another.Nio's "ups ...