If you had the prompt and the output, and you knew your work was in the training data, you _could_ retrain the whole model minus your work, and then feed the same prompt back in.
piece of cake. Load up copilot and start typing a comment that credits yourself for your work. It will autosuggest somebody else's real name and email address that you can search up and validate.
When a company decides to create an alternative to thing X they take care not to employ people who have worked on X. If AI creates a thing like X and has seen X I think there is probably a case.
Then if the output looked nothing like your work as it did for the inclusive model, you could prove your work was influential, possibly to the point of a © claim.
Probably quite an expensive way to do it, unless it's somehow possible to reverse specific inputs from a trained model :)