Sure thing.
1) Mic plugs into mixer
2) turn 48v power on
3) plug 1/4" out of mixer into PA mic input
(watch your gain)

If you have a stereo mixer, with effects, you can route one side to the vocal processor and use the TC effects, while the other side feeds the dry input for a second mic, or guitar etc, and use the mixer's effects.
Make sense?

WAIT< WAIT< WAIT !!!! Are youy trying to use the SAME mixer for input AND output to the QSCs? That's a bit more complicated, but very doable.

In that scenario, the channel that has your mic should not be sent to the QSC directly. Try this:

Mic into Ch 1 of the mixer. Keep channel fader ALL THE WAY OFF. Use a monitor send to feed the vocal input on Korg.
IMP: Make sure NO other signals are routed thru the monitor bus. This will confuse the harmonizer.
Call if you need me to walk you through it
215-284-1328