Had a big problem in Poland - a guy lied to me

No, Nigerian scam is sth else: known as Nigerian prince scam:
en.wikipedia.org/wiki/Advance-fee_scam

He said he wanted to transfer $20 million to the recipient's bank account. In exchange for transferring the funds out of Nigeria, the recipient would keep 30% of the total. To get the process started, the scammer asked for a few sheets of the company's letterhead, bank account numbers, and other personal information

In 1990s I actually laid my hands on a real scam letter from Nigeria sent to my business` address. I had no idea what it was about so I threw it away. I regret it today.

Don't.
You did the right thing.
These scams have been going since the seventies.
All quite laughable, but some morons fell for them.....

I regret getting rid of a curious document which won`t appear ever again. One day my grandkids could sell it at an auction.