Cook Noodles: Cook the lasagna noodles in a large stockpot according to the package directions, opting for the shortest cook time suggested. Drain and set aside.
Prepare Sauce: In a small mixing bowl, combine the Alfredo sauce, milk, and oregano. Whisk until the mixture is smooth and well blended. Set aside.
Chop Ingredients: Coarsely chop the cooked chicken. Using a food chopper, finely chop the artichoke hearts, red bell pepper, and onion. Place these chopped ingredients in a large mixing bowl.
Mix Ingredients: Press the garlic clove over the vegetable mixture. Add the shredded mozzarella and crumbled feta cheese. Mix everything thoroughly.
Assemble Lasagna: Spread 2/3 cup of the Alfredo sauce mixture over the bottom of a rectangular baking dish. Layer half of the lasagna noodles on top, slightly overlapping them. Add half of the spinach leaves over the noodles, then layer half of the chicken mixture on top of the spinach. Repeat these layers, starting with half of the remaining Alfredo sauce mixture. Finish by pouring the rest of the sauce over the top of the assembled lasagna.
Bake: Cover the baking dish with aluminum foil and bake for 45 minutes. Carefully remove the foil and continue baking for an additional 10-15 minutes, or until the lasagna is bubbly and golden.
Rest and Serve: Remove the lasagna from the oven and let it stand for 15 minutes to make serving easier. Cut into squares and serve using a large spatula.
