Nigeria could have been on this list, but there's a huge reason why it's not. For example, Nigeria is one of the highest oil producing states in the world and and it's government is very good and diplomatic with foreign exchange and trade, but the government is arguably the worst and most corrupt anywhere in the world, in reality, I'm using per Capita income against the nefarious inflation rate, it's easy to say some people lives rather poorly especially when you measure quality of life as well. Most of these countries here on the poorest list are not productive and do not have Lucrative natural resources as well, coupled with the fact that there's just a little bit of bad governance.
In reality, Nigeria could have been one of the richest countries in the world, it was rumored that in the 1960s, one man robbed the country so much that his grand children are still spending all that looted funds.

This is an enlightening read

@tipu curate