In a mixing bowl, combine Italian cheese blend with cottage cheese. In a separate bowl, combine both jars of Alfredo sauce, water, Italian seasoning, and garlic.
Now, assemble the layers. Spread 1/4 of the Alfredo sauce on the bottom of the slow cooker. Arrange a layer of 3-4 lasagna noodles on top. (It's okay to break the noodles to make them fit.)
Spread 1/3 of the chicken on top of the noodles. Spread 1/3 of the cheese mixture on top of the chicken. Spread 1/3 of the mushrooms on top of the cheese (optional).
Repeat these steps two more times (Alfredo sauce, noodles, chicken, cheese mixture, mushrooms). Top with the remaining Alfredo sauce. Cover all noodles as much as possible to ensure they cook properly.
Sprinkle shredded mozzarella cheese and dried parsley (optional).
Cover and cook on low 3-4 hours.