Not a single thing that will help the economy, but all will be combined to make a good economy. If Nigeria government force those exchanges to have offices in Nigeria, have some workers from Nigeria and regulate them like banks and using them to generate internal revenue, it would have been better.
Even if our government sets a framework/regulation for crypto, it does not mean centralized exchanges would launch physical offices in Nigeria, i don't see why they'll want to do that or be forced to do that. The government would only give them their own terms of the crypto regulatory framework, and if these businesses think they cannot cope with it, they'll simply have to discontinue their services to Nigerian customers.