No, that's still a case where the government has agreed that you can sue them. Every government being sued has agreed to investor-state dispute resolution in one or more treaties that they've signed (to encourage foreign investment).
The ICSID does not hear cases against countries that have not agreed to abide by its rulings.. so if you invest in a country that has not signed, you're SOL... they're not going to help you.
[1] https://www.theguardian.com/business/2015/jun/10/obscure-leg...