MindNode for iOS comes with MindNode for watchOS. It allows to view an outline of the most recent documents directly on your wrist.
To open a document, tap on it and the first level will appear. MindNode for Apple Watch shows one level of sub-nodes at a time. When a node contains notes or an image, tap on the note symbol at the top of an open node to view them.
Force touch opens a menu to show recent documents and to switch between seeing the whole Outline, or just a list of open tasks.