Mexus has nothing of value in Mexico. Their "mine" is uneconomic and worthless.
In fact, I am sure at this point Mexus would be THRILLED if the government took it, and their significant clean-up and reclamation cost obligations, off their hands.
But that is not going to happen. There is no chance that Mexico will nationalize precious metal mining any time soon, if ever. Lithium, as an energy metal, is a different story. But gold? Nope.