What happened

Nio (NIO 0.62%) stock has been unstoppable this week, having logged massive gains in the first half including Wednesday's jaw-dropping 20%-plus rally. This morning though, the Chinese electric vehicle (EV) stock is taking a breather and was trading down 5.7% as of 10:15 a.m. ET Thursday.

Nio just announced its delivery numbers for November, and it not only lived up to expectations, but also trumped rivals. Investors, though, aren't sure what to do with the EV stock after yesterday's run-up.

So what

In early November, Nio said it was on track to deliver a record number of vehicles in the months of November and December. I strongly believed its outlook, and the reasoning behind it, should convince investors to buy Nio stock while it was still languishing.

Today, Nio said it delivered 14,178 EVs in November, up 30% year over year and 41% sequentially. It was a record quarter, just as management expected it to be.

Nio's rivals also announced their delivery numbers today but didn't see as much growth as Nio. While XPeng's rose 14% sequentially in November, they were down almost 63% year over year as the company struggled to scale up production and deliveries of its flagship SUV, the G9, amid COVID-19 restrictions. Li Auto, meanwhile, saw its November deliveries surge 50% sequentially to a record high, but they were up just about 11% year over year. 

Now what

Shouldn't Nio shares have risen today given its solid delivery numbers? Turns out, the recent volatility in Nio's stock price is keeping investors on the edge. One of the biggest overhangs for Nio this year has been the COVID lockdowns and disruptions in China.

Yesterday, an official from the nation reportedly hinted that the nation may relax some of its zero-COVID norms. That prospect alone sent Chinese stocks, including Nio, skyrocketing. But such a huge one-day jump in Nio's stock price driven primarily by speculation made little sense. 

Unsurprisingly, some investors who may have bought Nio shares at its lows seem to be taking some profits off the table today, perhaps awaiting a better entry point again.

That's not to say you should sell Nio stock, too. Nio's worst days could, indeed, be over, and with its newly launched vehicles clocking good delivery numbers in November, the company could very well grow its revenue by 75% or more year over year in the fourth quarter. That could be a big bullish trigger for the EV stock.