Mix sour cream, condensed soup, and cilantro in a saucepan over medium heat; cook, stirring occasionally, until heated through, 3 to 5 minutes. Remove from the heat.

Spray a large skillet with cooking spray; add diced tomatoes, chicken, onion, and green chiles. Cook and stir over medium heat until onion is transparent, 5 to 10 minutes.

Preheat the oven to 350 degrees F (175 degrees C). Spray an 8x11-inch baking dish with cooking spray.

Spoon 2 to 3 tablespoons chicken mixture down the center of each warm tortilla, then sprinkle with about 1 tablespoon pepper Jack cheese. Roll each tortilla around filling and place seam-side down into the prepared baking dish. Pour sour cream sauce over tortillas and sprinkle remaining cheese over top.

Bake in the preheated oven until sauce is bubbling and cheese is melted, 25 to 30 minutes.