Monogame, Nez: Switch scenes, open menus

I am starting with Monogame and Nez library / engine and am struggling with the open menu. My original idea was that the game would be one Scene class, another's menu. On the Esc key, I'll set Core.scene to a new instance of the menu scene and remember the original scene. When the menu closes, I'll revert Core.scene to its original. However, this will not work; when the scene is replaced, it ends and I cannot restore it.

So my question is, how do I go about doing this? Obviously I have some flaws in my design, but I don't see the right way to do this. After opening the menu, I want to pause the game, show the menu (perhaps toggle multiple menu screens), and then turn off the game when the menu closes and resumes playing.