Step 1 : Introduction to the question "Which world leader did Donald Trump nickname “Little Rocket Man”?"
...Donald Trump began referring to North Korean leader Kim Jong Un as “Little Rocket Man” in 2017 during a period of heightened tensions between the United States and North Korea. The nickname was a reference to North Korea’s ongoing ballistic missile and nuclear weapons tests, which drew widespread international concern. Despite the heated rhetoric, the two leaders later met in a series of historic summits in 2018 and 2019, marking the first face-to-face meetings between a sitting U.S. president and a North Korean leader.