Nio (NIO 2.94%) was one of the hardest-hit electric vehicle (EV) stocks in 2022. Although Nio's deliveries rose steadily through the year, production and supply chain hiccups made it a bumpy ride even as rising costs weighed down margins. Investors were pinning their hopes on a stronger 2023, especially after management announced its growth plans some months ago. Turns out, Nio's challenges are far from over. The company's fourth-quarter numbers just came out, and there's one metric that's caught the market's attention for all the wrong reasons. Is Nio having real problems that should worry investors now, or should you get greedy while the markets are fearful and buy Nio stock on every dip? Nio's fourth quarter was a record Nio stock slipped after the EV maker slashed its fourth-quarter de