Trumps Mother was a naturalized Scottish Immigrant.
There is one of the several NBC opinions that believe you need two natural born citizens as parents to be NBC, but it's a small number of people.
There is another that says the status must come from the father, another that says a foreign born of a American NBC mother is adequate in most situations where security is not a issue, simply because US jurisdiction does not stop when a citizen travels overseas. Nor did it for British subjects pre constitution.
It is sufficient to say that these interpretations remain ambiguous, and I believe it is intentional.
Don't you mean two citizens as parents ( not natural born ). If it were natural born, then no descendants of immigrants ( and their descendants ) can ever be NBC.