The past 8 UN ambassadors (excluding Acting Ambassadors) and their job qualifications (only listing things directly related to foreign service, public policy, diplomacy, or war):
Samantha Power - Journalist, Yugoslavian civil war; Time Magazine columnist on foreign issues; author of three books on IR and foreign affairs; Executive Director, Harvard Carr Center for Human Rights Policy; Professor of Public Policy, Harvard; senior advisor to Barack Obama 2008; Special Assistant to National Security Council; Chair, Obama Anti-Genocide ("Atrocity Prevention") Board
Susan Rice - Doctorate in International Relations from Oxford, Rhodes scholar, foreign policy aide to Dukakis, member of the National Security Council under Clinton, special assistant to president for African Affairs, Assistant Secretary of State, foreign policy advisor to Kerry, Brookings Senior Fellow on foreign policy.
Zalmary Khalilzad - Professor of Political Science, Columbia; foreign policy advisor under Carter; Council on Foreign Relations fellow, State Department advisor, South Asia; senior advisor to Reagan for Afghanistan and Iran-Iraq; special advisor to Undersecretary of State; Director of RAND Corporation's International Relations unit; advised Chevron on trans-Afghanistan gas pipeline; signatory of Project for New American Century letter; US Ambassador to Afghanistan; US Ambassador to Iraq.
John Bolton - BA PoliSci / JD Yale; National Guard reservist; Senior Vice President for Public Policy, American Enterprise Institute; Assistant to James Baker for Western Sahara; Assistant Secretary for International Organizations and Affairs; Assistant Attourney General; Assistant Administrator and later General Counsel, USAID; Assistant Attorney General; Undersecretary for Arms Control; Council on Foreign Relations; Committee for Peace and Security in the Gulf
John Negroponte - Foreign Service Officer, 10+ years, including on the Vietnam peace talks, US Ambassador to Honduras; Assistant Secretary of State for Oceans; Deputy Assistant National Security Advisor; Ambassador to Mexico; Ambassador to Philippines; Deputy National Security Advisor; speaks five languages
Richard Holbrooke - Fellow, Princeton IR school; foreign service, Vietnam (USAID); Vietnam Advisor, Johnson White House; Special Assistant to Undersecretaries of State; participant in Paris Peace Talks; wrote Pentagon Papers; Peace Corps Director, Morocco; Foreign Policy Advisor, Jimmy Carter; Assistant Secretary of State, East Asia; Policy advisor, Al Gore for President; Board of Refugees International; US Ambassador to Germany; Assistant Secretary of State, Europe; Special Envoy to Balkans; wrote as journalist and author about Balkans and civil war there.
Bill Richardson - MA in International Relations, Tufts/Fletcher; Staff member, Senate Foreign Relations committee; State Department, Nixon admin; House of Reps negotiating committee for NAFTA; negotiator for Bill Clinton in Iraq; diplomatic back-channel work in many countries including North Korea (nominated for Nobel Peace Prize). I agree, Richardson has a pretty thin resume.
Madeleine Albright - BA PoliSci from Wellesley; MA Columbia IR; PhD Columbia IR (thesis on journalists in Czech Revolution); Chief Legislative Assistant, Senator Ed Muskie (who worked extensively on Foreign Policy); Congressional Liaison for National Security Council; Woodrow Wilson International Center fellow, wrote on Poland's Solidarity movement; Prof Georgetown, Eastern European Studies; foreign policy advisor, Ferraro; foreign policy advisor, Dukakis; transition head for National Security Council for Clinton
Okay, now let's look at Nikki Haley's qualifications related to foreign policy:
Nikki Haley - As governor of South Carolina, had some disputes related to immigration policy with federal government; Husband is in Army National Guard.