I did suspect this - AJ has recently been in Nigeria and there's a lot of very rich people there who would love to fund this type of spectacle (not including the Nigerian billionaire princes that email you every so often!). It would be a huge spectacle to hold an event like this in Lagos or somewhere and would be legacy defining for Joshua. The obvious issue with it is the logistics would be a nightmare. Probably one of the most challenging places in the world to hold an event like this - that alone makes it very unlikely for me. Intriguing idea though.
They've got NADA (Nigeria Anti-Doping Agency) and AJ's Uncle is CEO of the Agency so the testing will be fine.
Ah so Ruiz would allow Nigeria because they are very strict with PEDs and pharmaceutical abuse there? But he won't allow UK? Makes sense.