It should definitely be Nigeria. The Super Eagles might not be at their best now, but Nigeria has the highest number of professional players in Africa. If you take a headcount of African players who play abroad, you might ascertain that Nigeria has the highest population. Maybe the high population of the country contributed to this fact. Just like Brazil, Nigeria can boast of more football talent in Africa.
Another indicator of a football nation is the popularity of the sport at the grassroots. Football is the most popular sport in Nigeria and it is played by children in almost all the nooks and crannies of the country.
I support your choice, it's not because Nigeria is my home country but it's a fact, asides having the highest number of African players spread across different European leagues and other leagues too, Nigeria has produced a very good number of African best players if not the most so if they were not that good, they won't have been achieving that the most. Truth be told we have lots of talents that are yet to be discovered if only our government can look into our football sector, rebrand the national league then build more stadiums, make it more interesting and entertaining to watch, an average Nigerian male is lover of football but most folks who got talent don't pick interest to play cause we lack good amenities and facilities.
In those days for some of us that grew up in port Harcourt, we grew up watching sharks FC, dolphins FC, ocean boys and the rest of them at Port Harcourt township stadium. We saw local based player driving good cars and doing very well for themselves, most children in port Harcourt township then wanted to play football because of the glory we saw from those guys. Lots of private investigators helped to sponsor some of this teams with huge capital. But today, the economy has nose dived and private investigators are not interested in investing 1kobo into local clubs because they won't get a return of their investment, people don't even buy tickets as much
to even as possible to go watch football games anymore despite this huge population we have.
Rebranding the Nigerian football in Club side level is a lot of work to do, people need to see real changes, players should paid adequately as much as they could compete with other counterparts in different part of the world, we should build new stadiums and there should be huge promotion of the local leagues so that it can be attractive.