So far, there appear to me to be several main ways in which chicha de jora is made. These range in difficulty from trivial to a process almost indentical to what barley-beer homebrewers are familiar with.
The first is apparently how much chicha is made in people's kitchens. Bill Ridgely describes most of the others in his articles. Also note that the methods that include mashing use a batch sparge. That is, the sweet liquor (upi) is merely drained from the mash and there are no continuous additions of sparge water to the surface of the mash. Certainly sparging can be performed if desired, but it is neither traditional nor necessary (corn kernels have no husk and therefore do not form a filterbed). Chicha is traditionally allowed to spontaneously ferment.
For the last type (Modern), George Duarte suggests that ground, unmalted corn could be mixed with a small amount of crushed 2-row malted barley and boiled for 20 minutes or so to gelatinize the starch in the corn. This gooey mass would then be added to more water and barley malt and mashed as per 'normal' homebrew procedures. This could probably be sparged as usual.