This is actually how it's done in New Zealand. We have something called realme https://www.realme.govt.nz/, which is made by New Zealand Post (our government post service, with the benefit of offices all over the country to do the initial ID verification for account setup) and the Department of Internal Affairs (they do things like births, deaths, marriages, passports, and citizenship, so they're used to dealing with identity)
It's an awesome system that the US would be lucky to have. I say this as a dual citizen of both countries.
The parent poster might have dual citizenship by birth, which would be a different case than starting with only NZ citizenship and acquiring US citizenship later (or vice-versa).
It's an awesome system that the US would be lucky to have. I say this as a dual citizen of both countries.