Combine all ingredients through the shredded Italian cheese. Please 1/2 into the dip.
8 ounces cream cheese, 1/4 cup mayonnaise, 1/4 cup sour cream, 1/4 cup parmesan cheese, 1 teaspoon garlic powder, 14 ounces spinach, frozen, 3 ounces artichoke hearts, 1/2 cup shredded italian cheese, 8 ounces diced water chestnuts