There are lots of solutions to joblessness in Nigeria; some of which we can achieve individually.
Firstly we should start by showing love to one another. It may sound confusing but take for instance, I own a firm or employed in a reputable firm, If I get the opportunity to employ someone else, I will definitely start by someone I love and care about. Most people get opportunities to employ people but because they don’t care about the person, they rather neglect the opportunity.
Secondly, just as @sylviaebs highlighted another solution is learning a trade, become an entrepreneur and be able to also employ people.
Thirdly, another effective solution is by development, in the sense that if only our leaders will drop greed and invest money in development; like building of industries, acknowledging the qualified individuals for a particular job and employing them to work in their actual field. In that way, we will have more qualified people working in their various fields (accountants working as accountants not as administrators, an engineer working as an engineer not as a banker and so on).
Lastly, the rate at which the government bring in foreign investors should reduce. Nigeria has capable individuals that can be trained and will even do marvelously well compared to those foreigners.
Thanks!