Spray 4-quart slow cooker with cooking spray. Add lasagna noodles, chicken, onion, garlic, Alfredo sauce, chicken broth, basil, salt and pepper to slow cooker. Stir gently; stir in 1 cup of the cheese.
Cover and cook on Low heat setting 1 1/2 hours; stir mixture thoroughly until pasta is covered in sauce. Cover; cook 1 1/2 hours longer or until pasta is tender.
Gradually add spinach, carefully stirring to wilt; sprinkle with remaining 1/2 cup cheese. Increase to High heat setting; cover and cook 5 to 10 minutes or until cheese is melted.