Will iPhone 12 mini support Dual SIM with nano-SIM card?

Yes, I understand that. Models sold in China, Hong Kong and Macau will have dual sim slots. All other models will have one eSIM, and one Nano sim slot. This applies to all models of iPhones that have dual sim capabilities.

Only models sold in China, Hong Kong and Macau.

An internet search may not have revealed that fact.

It's the only part of the world where you can find dual sim iPhones.