In a large bowl, whisk together eggs, milk, cumin, salt, and pepper. Set aside.
Heat oil over medium-high heat in a large sauté pan. Cook the sausage until brown, then add the onion, jalapeño, and garlic. Sauté for 5 minutes, stirring occasionally, until the onions are soft and translucent.
Add the scrambled egg mixture and reduce heat to medium. Cook for 2-3 minutes, stirring frequently, until the eggs are completely scrambled. Stir in the tortilla chips, salsa, and cheese. Cook for 2 minutes, stirring occasionally. Taste and season with extra salt and pepper, if needed.
Optional toppings: chopped fresh cilantro, diced red onion, sliced avocado, diced tomato, salsa.