That isn't the topic at hand. The topic is the neologism "Christian nationalism" and using it as a term to foment political division by identifying an "other" that is OK to be against or even to hate. That is precisely the kind of thing I personally try to avoid.
There is no clear, concise definition of what "Christian nationalism" even is. The most common definition is a strawman one: someone basically describes "people I don't like", and then says "That is Christian nationalism". That kind of thing isn't helpful. It would be better to just describe it as "People that so-and-so don't like" or "Belief systems that so-and-so doesn't like". And in some cases, strawmen don't actually exist in the real world, or are very isolated, fringe, and small. I have yet to run into any of this so-called "Christian nationalism" in real life anywhere, and I know a diverse group of people with a very wide range of beliefs.
It's somewhat similar to listening to right-wing sort of people who are fearful of things on the left wing talk about conspiracies to "take our children away" and "make us all go live in camps" or something.