How to Make It
Preheat oven to 425°F.
Heat oil in a nonstick skillet over medium-high. Add chicken to pan; cook 4 minutes on each side. Remove from pan; cool slightly. Shred chicken; sprinkle with 1/8 teaspoon salt. Combine chicken, yogurt, and 2 tablespoons green onions in a bowl.
Heat a large cast-iron skillet over high. Add red onion and jalapeño; cook 4 minutes, turning occasionally. Add garlic to pan; cook 4 minutes or until vegetables are charred on all sides. Place remaining 1/2 teaspoon salt, jalapeño mixture, tomatoes, stock, and cumin in a blender; blend until smooth.
Place 2 tortillas in the bottom of an 8-inch square baking dish coated with cooking spray, tearing tortillas as needed to fit in a single layer. Spread 1/2 cup tomato mixture over tortillas in dish; top with half of chicken mixture and 1/4 cup shredded cheese. Repeat layers once with 2 tortillas, 1/2 cup tomato mixture, remaining chicken mixture, and 1/4 cup cheese. Top with the remaining 2 tortillas, remaining 3/4 cup tomato mixture, and remaining 1/2 cup cheese. Bake at 425°F for 15 minutes. Top with remaining 2 tablespoons green onions.