Prep the ingredients: Crack the eggs into a bowl, add a pinch of salt, pepper, and the milk if using. Whisk until the yolks and whites are fully blended and slightly frothy.
Chop the onion, pepper, and garlic. Lightly crush the tortilla chips so you have a mix of small and medium pieces.
Warm the pan: Set a large nonstick or well-seasoned skillet over medium heat. Add the oil and butter.
When the butter melts and foams, add the onion and a pinch of salt.
Sauté the aromatics: Cook the onion for 3 to 4 minutes until translucent. Stir in the chopped pepper and garlic. Cook for 1 to 2 minutes more, just until fragrant.
If using cumin and chili powder or smoked paprika, sprinkle them in now and stir.
Toast the chips: Add the crushed tortilla chips to the skillet. Toss gently to coat them in the aromatics and fat. Let them warm and toast for about 30 to 60 seconds.
You want them crisp but not browned.
Add the eggs: Pour the whisked eggs evenly over the chips. Let them sit for 10 to 15 seconds so the edges begin to set, then use a spatula to gently push the eggs from the edges toward the center, folding the chips through the curds.
Cook to soft curds: Continue gently folding every few seconds. Keep the heat at medium or slightly lower to avoid rubbery eggs.
Cook until the eggs are just set but still glossy and soft, about 2 to 3 minutes.
Add cheese and finish: Sprinkle the cheese over the eggs. Turn off the heat and cover the pan for 30 to 60 seconds to melt. Taste and adjust salt and pepper.
Garnish and serve: Top with chopped cilantro, a squeeze of lime, and any extras you like—tomato, green onions, salsa, avocado, or sour cream.
Serve immediately while the chips still have crunch.