Ecuador is not a party to TPP. They can always do the Cuba-thing and rule against Chevron. (The difficulty they face will be in enforcing that judgment beyond their own borders.)
Worth mentioning that several of the parties have extra motives beyond what is mentioned here publicly. Ecuador wants money. They are quite willing to assign their own pollution to Chevron, and collect Chevron money for what they themselves did. Anti-globalization people want to make it risky for any big developed nation corporation to do business in the third world, creating the principle that the corporation's assets could be seized at any time 'for the benefit of the people.' The greens want to stifle, stop, oil production in the Amazon basin, and everywhere else.