Step 1

Preheat the oven to 350 degrees F.

Step 2

Coat a 2-quart baking dish with nonstick cooking spray.

Step 3

In a large bowl, stir the chicken, 1 cup of the cheese, the condensed soup, the milk, the sour cream, the tomatoes and green chilies, and the ranch seasoning together.

Step 4

Place 1/2 of the chips in the bottom of the prepared baking dish and top with the chicken mixture.

Step 5

Cover the dish with foil and bake until heated through, about 20-25 minutes.

Step 6

Sprinkle the casserole with the remaining cheese and the remaining chips.

Step 7

Bake the casserole, uncovered, until the cheese has melted, about 5 minutes.

Step 8

Serve.