Kate Siobhan Nicholl is an Alliance Party politician, serving as a Member of the Legislative Assembly (MLA) for Belfast South since 2022.

The Alliance Party of Northern Ireland (APNI), or simply Alliance, is a liberal and centrist political party in Northern Ireland. Following the 2022 Northern Ireland Assembly election, it was the third-largest party in the Northern Ireland Assembly, holding seventeen seats, and broke through by placing third in first preference votes in the 2019 European Parliament election and polling third-highest regionally at the 2019 UK general election. The party won one of the three Northern Ireland seats in the European Parliament, and one seat, North Down, in the House of Commons, the lower house of the Parliament of the United Kingdom.