Main issue with that is your region has restrictions placed by Uphold and others for now. If you go to https://support.uphold.com/hc/en-us/articles/360026786712-Non-Supported-Geographies- you’ll see Nigeria listed at We are unable to offer new accounts in the following locations:
Often any country listed under non-supported by Uphold will not be able to be supported by Brave. As to why Uphold is not able to operate in your country, I’m not certain. Though I’m assuming it’s based on the restrictions by government talked about at https://www.bloomberg.com/news/articles/2022-11-27/nigeria-sec-to-avoid-cryptocurrencies-in-digital-assets-push and https://www.kitco.com/news/2022-12-19/Nigeria-looks-to-pass-new-crypto-legislation-to-keep-up-with-global-economic-innovation.html
Basically, they have to tread carefully as countries change their regulations. Nigeria and India right now are constantly talking of changes and modifying existing rules. Until it settles down and they have something more concrete, it’s hard to operate there. Businesses want to make sure they aren’t doing anything illegal and it’s hard to make big changes every time. So you’re likely stuck waiting until governments can make more permanent decisions that allow them to operate.