Generally, yes. No problem with that.
The only issues that might arise:
If the controlling PC moves the mouse, VNC will immediately set the mouse pointer to the location on the controlling PC. Therefore, if you move the mouse on the Mac, and somebody moves the mouse on the PC, the PC takes precedence.
Also, if you move the mouse on the Mac, the controlling PC will not see these mouse movements. Not even when you click somewhere or enter text.
If you type on the controlling PC, then the mouse pointer might disappear on the Mac's screen.