I agree with 41.
My ethnicity is mostly Scottish, although DNA has shown its not as much as I thought! I consider my background to be Scottish because of where I grew up, my accent etc.
However, my nationality is British. I hold a British passport, not a Scottish or English one, British. My husbands siblings have Scottish accents, two were born there, but they all have the same parents. Their parents were English. His nieces and nephews think of themselves as Scottish yet there are no Scots in their ancestry.
I'd love nationalists from wherever to have a DNA test. They might be surprised.