Which categories to include for capturing European (mainly Irish) demographics?

Hi! I am a PhD student using surveys to collect my data. I am American but am studying in Ireland. I'm having trouble narrowing down which categories to include for my nationality and ethnicity questions. The pre-populated (and my own knowledge) of options for these questions are very Americanized, which won't work here. Are there any suggestions as how best to capture/best practices of asking ethnicity and nationality questions in Ireland/the EU? Thanks!