University of Chicago/YouTube US ambassador to the United Nations Nikki Haley recounted when President Donald Trump bestowed the infamous "Little Rocket Man" nickname on North Korean leader Kim Jong-un. Haley, who appeared to find the incident amusing, said Trump called to ask for her opinion about using the nickname during a speech at the UN General Assembly. Haley said after Trump mentioned the nickname on Twitter and during his UN speech, other heads of state began referring to Kim as Little Rocket Man, also. During a moderated discussion at the University of Chicago's Institute of Politics on Thursday, the US ambassador to the United Nations, Nikki Haley, recounted when President Donald Trump pitched a cheeky nickname for North Korean leader Kim Jong-un. Trump initially referred to Kim as "Rocket Man" in a tweet in September: "I spoke with President Moon of South Korea last night.