Greek Chicken Casserole

nonstick cooking spray 1 cup finely chopped yellow onion 1 cup water 1 (10 ounce) package frozen chopped spinach , thawed and squeezed dry 1 cup uncooked[...]

4 cups cooked chicken or 4 cups turkey , chopped 3 medium zucchini , halved lengthwise and cut into 1/2-inch pieces (4 cups) 1 (10 3/4 ounce) can condensed[...]