Position a rack in the center of the oven and heat the oven to 400°F. Arrange the tortillas on a baking sheet and spray them on both sides with cooking spray until evenly coated. Bake the tortillas until lightly browned and crisp, turning once halfway through baking, 7 to 8 minutes. (Don’t worry if they’re not perfectly flat.) Transfer to paper towels and sprinkle with salt.
Meanwhile, beat the eggs with 1/2 tsp. salt and a few grinds of pepper in a medium bowl.
Cook the chorizo in a 10-inch nonstick skillet over medium-high heat, breaking the meat into small pieces with a wooden spatula, until cooked through and beginning to brown, about 5 minutes. Transfer the chorizo to a paper towel-lined plate and set aside.
Discard the fat in the skillet, add the oil, and swirl to coat. Add the jalapeño and half of the onion and cook, stirring, over medium-low heat until softened, 4 to 5 minutes. Stir in the garlic, and cook until softened, about 1 minute. Pour in the eggs and cook, stirring slowly and constantly with the spatula to break up the curds, until the eggs are set but not dry, about 2 minutes. Remove from the heat and stir in the chorizo.
Place 2 tortillas on each of 2 plates. Top with the chorizo-egg mixture, distributing it evenly, and garnish with the tomato, avocado, cheese, and remaining onion. Serve immediately.