So that's approximately around $652. If I just want you to invest then invest it in Bitcoin and hold it. But you know what, you're looking forward to a greater future of yourself then just do physical business. Are you already good in BTC or crypto trading? I bet not because if you are, you won't ask for it. That's the reason if you're going to want to spend that 1 million naira, use it for any business that you are aware of. And when you're in profit there, that's the time you can invest in Bitcoin through DCA, any amount will do and do it consistently.
650$ is good amount to invest but if OP is new to Bitcoin then it's better for him to follow DCA strategy like investing 10 or 100 dollars per week or month. It's not advisable for new one to invest all he has in bitcoin. Also bitcoin price is at 117k and price from here may go up or down we don't know. So if someone is investing 1 million Naira into bitcoin then their is risk that investment may get struck if price goes down. It's better to wait for price to come down a bit and then start gathering bitcoin through DCA.