Preheat your oven to 375°F (190°C) and grease a 9×12-inch casserole dish.

Heat olive oil in a skillet and sauté chopped onion until soft and golden.

Add minced garlic, chili powder, and cumin, cooking for an additional minute.

Stir in the cooked shredded chicken, mixing well, and cook until heated through.

In a separate bowl, combine salsa verde and sour cream until smooth.

Spread some salsa verde mixture in the bottom of the baking dish, layer half of the tortilla halves, half the chicken mixture, a cup of salsa verde, and half a cup of cheese.

Repeat the layering with remaining ingredients, gently pressing down to meld layers.

Top with the last tortilla layer, the remaining salsa verde, and cheese.

Bake the casserole for 15–20 minutes until the cheese is melted and bubbling.

Let cool for 10–15 minutes before serving to set the layers.