After buying tatuma squash on a whim, I had to find a way to use it. Tatuma, or Mexican white squash, is native to Latin America. Similar to zucchini in shape, size and texture, Tatuma has a soft green skin with a slightly firm white flesh. If you can't find tatuma, zucchini or summer squash can be substituted. If using zucchini or summer squash, which cook faster than tatuma, add to the pan 5 minutes before the chicken is done.