¿Cuál es su / tu / vuestra nacionalidad?
* ¿Cuáles son sus nacionalidades?
**¿Cuáles son vuestras nacionalidades?
*Also possible for "ustedes"
**Also possible for "vosotros, as"
The nationality of Costa Rica in Spanish is costarricense.
The Spain's nationality is Spanish.
Yes, but not exclusively. A nationality means, basically, that you could have a passport from that country and there are definitely Spanish nationals with Spanish passports. As the community answer below notes, Spanish is often used as an ethnicity for people who are not Spanish nationals, but have ancestors who were Spanish nationals and have Spanish or Hispanic culture.
Bernardo's nationality is Spanish.
Spanish
He is Spanish.
Spanish.
Spanish
It is "nacionalidad".
He has Spanish nationality.
he is spanish he is spanish
Translation: tu nacionalidad