Since Nx 8.12 you can do it by using the move schematic (or mv) to 'move' the app to the same place but with the new wanted name.
For example, if I want to rename my 'oldNG' app to be called 'newNG', I can do that like so:
nx g @nrwl/workspace:move --project oldNG newNG
Or nx g mv --project oldNG newNG if I want to rename app from my default collection. (provisioned in angular.json).
If I want to move this app to different place- I just need to include the destination in the new name of the app, like so:
nx g @nrwl/workspace:move --project oldNG destination/newNG
Read more:
https://nx.dev/latest/angular/plugins/workspace/schematics/move