In a small skillet, bring chicken broth to a boil over medium heat. Add scallops, cooking just until they turn white (2-4 min.); set aside. In a large skillet, heat olive oil over medium heat; stir in onion, mushrooms, garlic and Italian seasoning, sautéing until onions are soft (about 3 min.). Add shrimp, crab meat and scallops, stirring to combine. Brush the bottom of a 13x9" glass baking dish with olive oil; line the bottom of the pan with 2 pasta sheets. Top with 1/2 of the seafood mixture, 1/2 of the sun-dried tomatoes, 1/2 of the Alfredo sauce, 1/2 of the spinach and 1 cup cheese. Layer with 2 additional lasagna sheets and remaining seafood mixture, sun-dried tomatoes, Alfredo sauce, spinach and 1 cup cheese; top with last 2 lasagna sheets. Bake, covered, in a preheated 350° oven 45 min.; remove foil. Top with remaining cheese and continue baking until cheese melts (10-15 min.). Let stand, covered, until set (about 10 min.).