That's exactly right; just this week there was a successful (or so claimed) ICBM intercept test by the Pentagon; the USG has desired full spectrum nuclear dominance and missile defence primacy so as to prevent themselves from reaping what they intend to sow.The us has vindicated China suspicion that their missile defence system is aimed at her (and russia)
Therefore China must (and already doing) increase their nuke warheads to at least 1000 to ensure mad
In the eg in that twitter post, it's not unfeasible to expect the US to do something as stupidly irresponsible as launch a mini-nuke at Fiery Cross reef (perhaps with the same damage as the MOAB) and then hunker down, daring the Chines to do something about it.
You saw this behaviour from Trump after launching tariffs against China then having the nerve to demand that China "not launch reciprocal tariffs against the US", like the old Polish saying, 'the US cries out in pain as he strikes you'.
Secondly, this admin. has demonstrated its white supremacist leanings so would not be particularly bothered by radioactive fallout afflicting the rest of east Asia since it would kneecap any notion of Asian superseding white nations.