Biggest one in that region is Argentina, and the US has been sanctioning them a lot lately, to the point where their country reached 3 digit increased inflation, 3 digits!
So I suspect this is all done on purpose to further lower the price of lithium (corroborated with the lithium price in the global market, fishy fishy) so the US can have their green transition at lower cost, it's a sad era for South Americas yet again..
This nationalization is a step in the right direction, but that doesn't matter if it ends up in the hands of foreign countries for cheap...
They should keep the lithium for themselves, manufacture batteries themselves and sell them with very high margins, if they don't do that, then something is fishy in the Chile/Argentina government..