Yes, of course. But not simultaneously, because only one of the monitor's inputs can be active.
If two systems are to be visible on the monitor at the same time, one would have to realise it like this:
The monitor is connected to a PC running the base system (host) and a virtual machine (VMware).
VMware has technologies that make it possible to display both sessions on the monitor and to operate them with the same mouse/keyboard.
The whole thing "feels" like two PCs (also needs 2 operating systems). Just like running 2 PCs ....
Of course, this solution needs a powerful machine (i7 class, 16 GB RAM, fast SSD (Samsung pro) as system drive).