There is no explicit support for nesting Navigations, mainly because we cannot currently create a bookmarkable URL for the nested navigation pages.
However, you can mock this behaviour by inserting the left panel as a widget into the content, and keeping the left panel unchanged whenever you navigate to a new page. So while the entire content panel changes when you navigate, the same left panel shows up every time, and it appears as though only the right panel is changed.
If you are using this behaviour to create a sidebar and content panel, for example, you can also always use nested lists in your sidebar to navigate to sub-pages in the right content panel.
Hope this helps. If this doesn't work for your use case, feel free to explain it further and we will try to help you.