Preheat the oven to 180°C / 350°F.

Combine ground cumin, paprika, dried oregano, onion powder, garlic powder, salt, black pepper, and cayenne pepper in a mixing bowl.

Set aside 1 rounded tablespoon of the spice mix for the tomato passata sauce. Reserve the remaining spice mix for the chicken.

Heat 2 tablespoons of olive oil in the large skillet over medium heat. Stir in the all-purpose flour and cook for 1 minute.

Whisk in the chicken broth and bring the sauce to a boil.

Add tomato passata and the reserved spice mix. Season with additional salt and black pepper, then simmer for 5 minutes.

Coat the chicken breast pieces with the remaining spice mix. Heat 2 tablespoons of olive oil in the large skillet over medium-high heat.

Cook the spiced chicken until browned and cooked through, about 6 to 8 minutes. Transfer it to a bowl and slice it.

Add the sliced onion, fresh garlic, red bell pepper, and green bell pepper to the same skillet. Cook over high heat until softened and lightly charred, about 6 to 8 minutes.

Stir frozen corn kernels into the charred vegetables. Cook until the corn is hot, about 2 minutes.

Brush one side of each corn tortilla with sunflower oil. Heat each tortilla in a dry frying pan for 10 seconds per side.

Spread about 240 ml / 1 cup of tomato passata sauce over the base of the baking dish.

Layer 6 corn tortillas over the sauce. Top them with half of the tomato passata sauce, half of the sliced chicken, and half of the vegetable mixture.

Scatter half of the spring onions and half of the cheddar cheese over the filling. Repeat the layers with the remaining corn tortillas, chicken, vegetables, spring onions, and cheddar cheese.

Spoon the remaining tomato passata sauce over the top. Finish with the remaining cheddar cheese and spring onions.

Bake uncovered at 180°C / 350°F until bubbling and golden, about 30 minutes. Rest for 5 minutes before serving.