Somehow my default keyboard got changed. I used to be able to go to Settings -> Language and Input and then there was something that would let me change the keyboard. Now under "Keyboard and input methods" I only see "Virtual keyboard" and "Physical Keyboard". When I select the former it lists all the keyboards I have installed and enabled, but doesn't show me which one is the selected keyboard. If I tap any of the keyboards it takes me to the settings for that keyboard, which doesn't provide me with any way to make that keyboard the default. Long pressing does the same thing. There is nothing helpful under the menus. If I tap on "Manage keyboards" it shows me all the keyboards installed, and a mini-slider showing if each is enabled or not and allowing me to change. But again, nothing to set the default!
How do I change the default keyboard in Android N?
Update: Apparently Google doesn't even know how to do this - I contacted chat support and the agent wasn't able to help me!