After these terms as minister, Nuseibeh became an ambassador of Jordan, serving at several high-profile posts. His first assignment was Egypt, where he served from 1968 to 1971. He continued as ambassador in Turkey, being stationed there between 1971 and 1972. He left the Middle East for Europe in 1972 to become ambassador to Italy, Switzerland and Austria, serving until 1974. Nuseibeh changed continents once again when he became the Permanent Representative of Jordan at the United Nations in New York, United States in 1976. During his time as Permanent Representative he on numerous occasions fell out with the Israeli Representative Yehuda Zvi Blum. In December 1980 Nuseibeh partially based a speech on The Protocols of the Elders of Zion, an anti-semitic hoax purporting to describe a Jewish plan for global domination. For the speech he received severe criticism from Blum. Early in 1982 they fell out over the position of Palestinians in Jordan and Israel. Blum wished to point out that Palestinians already had a home in Jordan and referred to the country as "the Palestinian Arab State of Jordan", while Nuseibeh responded by calling Israel "the Israeli entity". During the discussion of the 1982 invasion of the Falkland Islands in the United Nations Security Council, Nuseibeh assured the Argentinian Representative, Eduardo Roca, that Jordan would vote against the United Kingdom. However, after a conversation between Nuseibeh and United Kingdom Representative, Anthony Parsons, the Jordanian vote would later be in favor of the United Kingdom in United Nations Security Council Resolution 502. Nuseibeh served as President of the United Nations Security Council in October 1982 and he retired as Permanent Representative in 1985.