ISDS already in use
The Case Studies section of the wikipedia page for ISDS is interesting:
The Indonesian government was sued in June 2012 by a London-based mining company Churchill Mining after the local government revoked the concession rights held by a local company in which the firm had invested. The government is countering the Churchill case, claiming that Churchill did not have the correct type of mining licenses.
In October 2012, an ICSID tribunal awarded a judgment of $1.8 billion for Occidental Petroleum against the government of Ecuador. Additionally, Ecuador had to pay $589 million in backdated compound interest and half of the costs of the tribunal, making its total penalty around $2.4 billion. The South American country annulled a contract with the oil firm on the grounds that it violated a clause that the company would not sell its rights to another firm without permission. The tribunal agreed the violation took place but judged that the annulment was not fair and equitable treatment to the company.
Irish oil firm Tullow Oil took the Ugandan government to court in November 2012 after value-added tax (VAT) was placed on goods and services the firm purchased for its operations in the country. The Ugandan government responded that the company had no right to claim tax on such goods prior to commencement of drilling. The case also attracted criticism for Tullow's use of local legal representation, Kampala Associated Advocates (KAA); the Ugandan law firm was founded by Elly Kurahanga, the president of Tullow's operations in Uganda and concerns were raised over his impartiality in the issue.
Tobacco major Philip Morris sued Uruguay for alleged breaches to the Uruguay-Swiss BIT for requiring cigarette packs to display graphic health warnings and sued Australia under the Australia-Hong Kong BITS for requiring plain packaging for its cigarettes. The company claims that the packaging requirements in both countries violate its investment.