Preheat oven to 190 degrees C. Spread the marinara sauce in the bottom of a 20x30cm glass baking dish; set aside.
Heat oil in a frypan over medium heat; cook and stir mushrooms until they soften, about 5 minutes. Stir in spinach and cook until hot; remove from heat.
Stir together the chicken, ricotta cheese, Parmesan cheese, oregano and the cooked spinach mixture in a large bowl. Season to taste with salt and black pepper. Spread about 1/4 cup of the mixture on each lasagne strip. Roll the lasagne up and place seam-side down into the prepared baking dish. Repeat for each strip. Spoon Alfredo sauce over the rolled pasta.
Bake covered in the preheated oven for 40 minutes. Uncover; sprinkle with mozzarella cheese and pine nuts. Return to the oven and bake until the cheese is melted and bubbly and the pine nuts are toasted, about 10 minutes. Serve hot.