See, most people who eat at the Mexico QS get the tacos or nachos (and I enjoy the nachos, but they're just basic nachos, though maybe a step up from other WDW nachos.) But the real winner, the secret delicious menu item that no one seems to ever mention, is the pollo cascabel (AKA arroz con pollo bowl): "Marinated Grilled Chicken, Rice and Corn topped with a spicy Tomato Sauce, Pickled Onions, Queso Fresco, and Cilantro."
It's so tasty. The sauce has a great flavor, the pickled onions add a nice brightness, and I'm a sucker for cilantro and queso fresco. Definitely recommend giving it a try.