hey, if you check the API explorer (look at the user object and check the collections tab) you'll see this probably isn't possible. You cannot call on the project collection from a user report, so no nested column for you.
As Christina mentioned, a project report filtering on access level, grouped by owner would get you a list of projects owned by your planner license people.
From the user report you could use EXISTS statements to pull out a number of things, such as users who don't own projects, users who don't create projects, users who haven't owned a project in the past year, and/or so on. In addition to all your user filters (e.g. user is active, user has a planner license) you would also add at least the following:
EXISTS:a:$$EXISTSMOD=NOTEXISTS
EXISTS:a:$$OBJCODE=PROJ
EXISTS:a:ownerID=FIELD:ID
i.e. there is exists no [line1] project [line2] where the project's owner ID field is the same as your user's ID [line3].
Obviously, swap out ownerID with enteredByID if you want to find who hasn't been creating projects. Or add entry dates if you want a feel for who hasn't owned a project in the past year (for example)
