The UN (and all of its agencies) do not hire pilots at all....all aircraft contracted by the UN are owned and operated by various companies.
One of the requirement for pilots flying on UN-aircraft ist time on type, depending upon the size of the aircraft between 500 or 50 for Copilots...
There will be hardly anyone hiring a non-ex-military pilot without type rating or experience to fly in a warzone; there is a reason why ex-military are hired for those, because they have the knowledge and experience that civil trained pilots do not have..