"My sister Julie has made this recipe for years and it has turned into a family favorite. Kids and adults love it and I love that it is easy to prepare and tastes wonderful. It is truly a comfort food. Goes great with a lettuce- and fruit-type salad along with garlic bread."
Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking dish.
Bring a large pot of lightly salted water to a boil. Cook lasagna noodles in the boiling water, stirring occasionally until cooked through but firm to the bite, about 8 minutes. Drain.
Combine chicken, milk, ranch dressing mix, and black pepper in a skillet; bring to a boil. Reduce heat and simmer until sauce is reduced and thickened, about 20 minutes.
Layer 4 lasagna noodles in the bottom of the prepared baking dish. Spread 1/2 the sauce over noodles. Sprinkle 1/2 the Cheddar cheese and 1/2 the mozzarella cheese over sauce. Repeat layering with remaining ingredients.
Bake in the preheated oven until bubbling and cheeses are slightly browned, 30 to 40 minutes. Cool for 10 minutes before cutting.