Preheat oven to 375°F (190°C) and lightly grease a baking dish
In a large bowl, mix Greek yogurt, mayonnaise, garlic powder, salt, pepper, and 1 teaspoon chili powder until smooth
Add cooked chicken, corn, and half of the cheese, mixing until well combined
Transfer mixture into the baking dish and spread evenly
Sprinkle remaining cheese and remaining chili powder on top
Cover with foil and bake for 25–30 minutes
Remove foil and bake another 10–15 minutes until bubbly and slightly golden
Remove from oven and let it rest for a few minutes
Drizzle fresh lime juice over the top
Garnish with cilantro, green onions, and optional chilies before serving