Questions asked are usually a combination of position specific question (Can you tell us how your competences align with the position? Tell us about yourself), and standard UN questions that can be found fairly easily online (https://uncareer.net/interview-questions). In my case, they included why do you want to work for the UN? and Tell us about when you had a communication issue in your work and how you resolved it?

Tell me about a time when you had to adapt quickly to a significant change at work. What was the situation, and how did you respond?