Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the shredded chicken, cream cheese, sour cream, cheddar cheese, pepper jack cheese, chopped jalapeños, garlic powder, onion powder, smoked paprika, salt, and pepper. Mix until well combined.
Transfer the mixture into a greased 9x13 inch baking dish, spreading it evenly.
In a separate bowl, mix the crushed cornflakes with olive oil. Sprinkle the cornflake mixture evenly over the chicken mixture in the baking dish.
Bake in the preheated oven for 25-30 minutes, or until the casserole is bubbly and the top is golden brown.
Remove from the oven and let it cool for a few minutes before serving.