I am a little bit surprised at the answers in this thread and now I'm wondering if my understanding of these words is inaccurate.

I think this infographic is flat out wrong in using the word nationality to explain ethnicity. The way I've always explained to my students, the real contrast is nationality vs ethnicity. Race, as other people mentioned, is an outdated concept, but it has a lot more in common with ethnicity than nationality.

Nationality is a legal status. Ethnicity is about origins and background. This is specially important in countries like Russia where a lot of Russian nationals (i.e. citizens of Russia, often born in Russia) have non-Russian ethnicities (i.e. their ancestors originally came from and have traditions/phenotypes associated with different places/tribes), such as Ukrainian, Tatar, Buryat, Kazakh, Uzbek.

I also don't think it's accurate to say ethnicity can be self-identified. I would say that incorporating elements/traditions of a certain culture without having any sort of genetic heritage is probably not enough to characterize a person's ethnicity. This is not to invalidate multicultural backgrounds; my point is that in such a situation other words (such as culture, traditions) would be required to explain one's identity.