The reason you're not seeing the nodes you expect to see in the screenshot above is that whenever you switch to the Fusion Page from the Edit page, Resolve turns whichever clip that currently intersects the Edit timeline playhead into a Fusion clip, and populates the node tree with a MediaIn and MediaOut node. Your Fusion composition should be listed there. With all of the bins selected, Resolve shows all of the available content in your project. To see absolutely everything in your project, first you need to expose the sidebar of the media pool, then select the 'Master' bin and all children of it by shift-clicking the last item in the list of bins. If you don't see your Fusion Clip there at first, don't panic. Resolve's Media Pool contains all of the elements you've imported or created within the context of the currently open project. If your Fusion clip doesn't exist on your edit timeline (there are a few ways to do this), then to find it within the Fusion page, you'll need to navigate to it through Fusion's 'Media Pool' tab.

If your Fusion clip exists on your edit timeline, then when you're in the Fusion tab, you'll see it listed if you activate the 'Clips' panel (at the top of the screen, or under Workspace->Show Panel in Workspace->Clips) It depends on how you created the Fusion compositions in the first place.

Fusion in davinci resolve