It doesn't appear to be possible to use the Outcome value selected in a NWC Task form to set another control's required, visible, read-only attributes via formula. The Outcome control isn't available in the list of Form controls. Why not?
My specific use case would set the Attachment control from required to not required if a "Stop Change" Outcome value is selected.
Thank you very much for posting your feedback for our review. At this time, due to very low votes, we will not be adding this request to the near-term backlog. And we are focused on other highly requested features such as Form Participant permissions, Repeating sections re-usability, etc. Please keep the feedback coming as it is critical for our longer-term planning.