If Trump "pardons himself", as a power explicitly granted under the Constitution (although annoyingly not explicitly barred from use by self) it is open to scrutiny by the guardians of the constitution (much like the guardians of the galaxy, but waaaaaaaaaaay less spandex) SCOTUS.
However they can only review it, if it is used in a US court of law.
I agree with the NYT article, that there is a real danger that simply by inaction, the US courts could give the appearance that it is actually valid.
Bald note for US readers: If Trumps waving his self pardon around does result in courts deciding not to try him, you have effectively created a route whereby someone can put themselves above the law. And much as you might like to play with language, that is what a King does. A monarch. 244 years after you rather pompously decided you didn't like Kings, you will have finally got one back again. I just hope you are honest about it, and have a coronation, and knock up a crown.
Obviously the whole point of a Monarch is to keep the Monarchy going, so you're going to get the first born Trump as heir.
Oh, and even hated King George was not above the law of Britain. We did away with that in 1649. So not only have you regressed, it's not 1775 you are welcoming in, but more 1509. Think Henry VIII
I posted a joke of Kim Jong Un upthread. Maybe it's not so funny now ?