Preheat the oven to 375°F.
In a large oven-safe skillet, melt the butter over medium heat.
Add the onion and cook until softened and translucent, about 3–4 minutes.
Stir in the flour and seasonings (salt, pepper, cumin, garlic powder, chili powder).
Cook for 1 minute to remove the raw flour taste.
Slowly whisk in the chicken broth until smooth and slightly thickened.
Add the sour cream, cream cheese, and diced poblano peppers.
Stir until the mixture is smooth and creamy. Bring to a simmer and cook for 5 minutes.
Stir in the shredded chicken and corn until well combined.
Cut the tortillas into quarters and fold into the skillet, coating them in the sauce.
Spread evenly in the skillet.
Place in the oven and bake uncovered for 10 minutes.
Remove and sprinkle with the shredded Monterey Jack cheese.
Return to the oven for another 5 minutes, or until the cheese is melted and bubbly.
For a golden top, broil for 1 minute.
Remove from the oven and let cool slightly before serving.
Garnish with fresh cilantro, sliced jalapeños, chopped red onion, or cotija cheese if desired