> You’re mixing up nation states and ethnostates.
I'm not, using common definitions. They just happen to usually be the same because culture and ethnicity are often very tightly coupled.
The factors you're talking about (border sovereignty and determination of citizenship/residency) are all related to being a "state" and have relatively little to do with being a nation, which is just a shared culture. A nation state is the term for a state, the political entirely, whose population shares a broadly homogenous culture. If you choose to define the US as a nation-state, then it blunts the "nation" portion to the point of redundancy, as the culture of sharing a government is enough to define a nation. Do a bit of research here and at a minimum you'll find that the US being a nation state is widely disputed. But we can agree to disagree because again, everything you're talking about is political determination related to statehood. Nation is irrelevant.
> Deportation isn’t a “punishment.” It’s restoration of the status quo ante in response to someone entering illegally
This is weak semantics. A goal of retribution is not a requirement for some act to be a punishment. It is simply "the imposition of an undesirable or unpleasant outcome upon a group or individual, meted out by an authority as a response and deterrent to a particular action or behavior that is deemed undesirable or unacceptable". Defacto it is a punishment. But this again doesn't matter even if you choose to find it not a punishment, it is still unjust. It may also be a return to the status quo, but so too is, for example, returning someone to prison for a parole violation, and I think you'd be hard pressed to define that as anything but a punishment.
> If you build a house on someone else’s land, they can force you to tear it down.
I'm dubious of this. You likely could not compel me to tear it down. You could sue to cover the costs, but if I had no money there are limits on what you could do.
I'm contending that deportation is similar. It, at a minimum, is not a just way to "restore the status quo".