In the Land of Israel, a Seder is only held on the first night of Passover; and outside of the land of Israel, there are two seders — on both the first and second night. Is an Israeli with dual citizenship (i.e. both a citizen of the land of Israel and the U.S.A.) required to have two Seders while visiting the U.S.A. during Passover? Is an American visiting Israel required to do the same?
If the individual lives in Israel and is just visiting, he or she only does one seder regardless of citizenship. Conversely, if an individual lives in America and is just visiting Israel, he or she would be required to have two sedarim (plural for seder). It has to do with where you live, regardless of the citizenship you hold.
However, the entire issue is multi-faceted and complex, and you would do well to speak with a reliable rabbinic authority to flesh out all the issues.
Have a happy Passover!
Rabbi Azriel Schreiber