Heat olive oil in a large skillet over medium-high heat. Cook and stir onion and garlic in hot oil until fragrant, about 5 minutes.
Stir zucchini and corn into the onion mixture. Cover the skillet and continue cooking until the zucchini is tender, about 10 minutes more.
Pour buttermilk into the skillet. Season the corn mixture with salt and pepper; stir. Bring the mixture to a boil, reduce heat to low, and continue cooking until hot, about 5 minutes more. Sprinkle with Chihuahua cheese.
