Chaco tucumana is a species of mygalomorph spiders of Argentina, named after its type locality: Tucumán.

As in C. obscura, smaller specimens are much lighter in color, and it has darker spots that are evident on the sides of its cephalic region, the apex of femora, base of the patellae and lateral tibiae and dorsal abdomen.

The cheliceral tumescence is flat, covered with thin setae on its inferior half.

The cephalothorax, legs, and palpi are blackish-brown; the abdomen is brown with light-brown spots.

The sternal sigilla is small, submarginal, and of medium depth; the sternum is rebordered.