I don't know if this is possible but it would certainly be useful it was.
If a manager is a decision maker for a number of workflows and goes on leave they have to remember to visit all the WFs and delegate another staff member to act of there behalf. Of course they won't remember to do this and they're too busy anyway so what they really need is a single place that lists all their WF and they can delegate each WF a temp delegate as needed.
All this information must be in the Nintex DB and a simple web app could be created to get and set delegate info.
Has someone written such an app or knows of an API to the database that would allow access to WF delegation.