After all, one imagines that if they really put their mind to it, Japan, Taiwan, and South Korea could all go nuclear in a period measured in small single-digit months. They really aren't that hard [1]. If, indeed, they aren't already effectively nuclear. (We'd probably know if they'd ever tested a weapon. We wouldn't necessarily know if they'd actually built one. If I were them, I totally would have.)
One of the interesting aspects of the whole Inevitable Rise of China narrative storyline is that it has been predicated on their continuing to develop and primarily use soft power. I tend to agree if they focused on that, they have many avenues available for major growth, if not outright exceeding the US in power, certainly by the end of the 21st century. The equations for all of that have to be reconsidered from scratch if they become a dictatorship, become subject to the whims of a single man, and decide to primarily pursue hard power. If they become outright aggressively belligerent, they are surrounded by countries powerful enough to at least put a dent in their ambitions in Taiwan, Japan, Korea, and India, all of whom are already generally US allies and would be chased into the US's arms fully by a belligerent China. China is not currently powerful enough to take on that coalition, nor is it clear to me where they would get allies for that push. (It seems unlikely that the EU would full-throatedly throw in their lot with China. Russia, other than being nuclear, isn't really a strong enough military or economic power against that sort of coalition to be the deciding factor.) Furthermore, China's internal power is IMHO more delicate than may meet the eye; if China devotes more resources into hard power internally and the middle class starts to fade, internal social unrest is going to be a major problem. Even if China manages to suppress its most overt expressions, unrest still manifests itself in many little ways.
The best move for China is slow and steady, to win the race. But if one man decides that's not fast enough, well, a lot of people could end up dying for that decision and my guess is China would still not come out on top.
[1]: https://io9.gizmodo.com/this-experiment-proved-that-anyone-c...