I am a dual national of countries X and Y and I'm living in third country Z.
I've entered country Z on passport X.
If I'm asked about my nationality in general on documents (but no question directly refers to second nationality), am I obligated to say both X and Y, or may I disclose only one or the other?
If I'm explicitly asked 'do you hold a second nationality' am I obligated to disclose it?
Thank you in advance.