This discussion of nuclear versus conventional has been discussed ad nauseum.
Everyone needs to accept that nuclear carriers are simply better if you have the money, industry and technology to support it. Everyone knows that the type of carrier that the PLAN wants to settle with is a nuclear powered super carrier in the future -- the fact that they aren't going for one right now or that CV-18 is not one, means that circumstances are not sufficient for them to go for it yet.
The advantages of nuclear power for increasing aviation fuel volume, improving ability to move independently indefinitely which reduces the burden of a task force's replenishment needs, as well as the indefinite electrical power generation capability if the design is able to support it, are all highly useful traits for a high intensity conflict even if it was fought in the pacific.
The idea that nuclear power is only useful for long distance deployments is simply untrue.
If the PLAN seeks to be able to seriously contest air and sea control outside of the second island chain, a fleet of nuclear powered super carriers would significantly benefit that mission (alongside a host of other overall joint PLA capabilities of course).
I would also suspect that if CV-18 was nuclear powered, that many people here would be singing the praises of nuclear power and celebrating such an advancement and its material capability enhancements relative to conventionally powered carriers.