No, he can't. But he can purchase Chinese products in bulk in the form of exports. And that's the reality of the analogy - the value generated by Chinese workers is being deflated globally (but especially relative to the US since it is their currency that is the main exchange medium).
This could very well be a strategic decision by the Chinese government, but it is a meaningful decision regardless. It means Chinese individuals and companies are incentivized to sell to the West and to immigrate to the West, since they get a much better deal for the value of work.
Yeah, they can import more, in theory, no one denies that. The US is the strongest import market globally after all.
That's one use of looking at nominal GDP. But that's nowhere near the JUSTIFICATION needed to bring it ahead so much from all the other more useful economic indicators.
In fact, the reason it is used so much is that it is best used by the US gov. to whitewash its failures in the real economy.
BECAUSE, yes, John from California can theoretically import more now, but in the process, he lost the ability to do so, since his real wage and disposable income fell now due to the US poorly managed real economy.
In the end, all that nominal GDP excess is just some inflation, and excess profit of some company on some book.
By actually paying for stuff more, John increased nominal GDP but DECREASED his ability to import from China.