You can't add a local bank account / debit card in your country. You can only link a visa credit card.
Plus the option to receive Paypal payments is sadly not available in Nigeria. You can only send payments for purchases funded by your (confirmed) credit card.
Paypal varies a lot country to country and can only offer the services that the banks / governments of that country allow it to offer. There are quite a few countries unable to receive Paypal payments.
