Code:
FontInstance:SetFont("font",size,["flags"])
so
Code:
ChatFrame1:SetFont("Fonts\\FRIZQT__.ttf", 11, "OUTLINE, MONOCHROME")
Believe FRIZQT__.ttf is the normal chat font. Could be wrong.
If you are using an addon for the actual font, your addon should change it even with this code; since font addons normally overwrite them anyway. But the monochrome should stay. I use prat all the time, and never had a problem with aurora with it. Might just be tekticles?
EDIT: I am now A Rage Talon Dragon Guard, RAWR :>