How do you say nationality?

"Nationality" is already the correct word to use. It refers to the status of belonging to a particular nation.

However, if you are looking for synonyms or different ways to express the concept of nationality, here are some options:

Formal:

* Citizenship

* National origin

* Place of birth

* Country of origin

Informal:

* Where you're from

* Your roots

* Your heritage

* Your background

The best option depends on the context and the level of formality required.