Preheat oven to 350 °. Lightly spray a 2 quart casserole dish with cooking spray.
In a large bowl, stir together the condensed soup, sour cream, milk, taco seasoning and can of tomatoes until well mixed. Add in the chicken and 2 cup of the cheese and stir to combine.
Spread half of the crushed chips into the bottom of the prepared baking dish, then spread half of the chicken mixture, the rest of the Doritos, and then the rest of the chicken mixture. Add the remaining 1/2 cup cheese on top.
Cover the dish with foil.
Bake for 30 - 40 minutes. Garnish with cilantro if desired.
Notes
This dish is great served over some shredded lettuce and diced tomatoes.