Application Switcher showing up on wrong monitor display
The application switcher appears on the display where the Menu Bar is placed (the primary display).

However, if you have enabled Automatically hide and show the Dock in System Preferences → Dock, the app switcher will appear on the display which has last shown the Dock.

You can change the display which has last shown the Dock by moving the cursor to that display, move the cursor to the edge which houses the Dock and make the Dock appear momentarily.

This is the simplest approach to change the display on which application switcher needs to be shown in a multi monitor setup.