To picture 230 million people, think of this: it is more than three times the population of the United Kingdom, and almost the same as the United States. Yet Nigeria fits all those people into a country only about four times the size of the UK.
Most Nigerians are young. The average age in Nigeria is 17. Compare that to the United Kingdom, where the average age is around 40. That means Nigeria is full of children, teenagers and young adults - one of the youngest countries in the world.
Lagos, the biggest city, is enormous. About 20 million people live in and around it. That is bigger than the whole population of Sweden or Portugal. The traffic is famous - the city can feel like it never stops moving. There are music studios, markets, beaches, and skyscrapers all packed together.
Because Nigeria has so many people, it is also one of the biggest economies in Africa. People work in farming, oil, films, fashion, banking, tech start-ups, and music. A new business idea that starts in Lagos can reach millions of customers without ever leaving the city.