Preheat oven to 400°. Sauteonion 'til tender. Stir in salsa and spinach and cook two minutes more. Transfer to 1 1/2 qt baking dish. Stir in two cups jack cheese, cream cheese, cream & olives. Sprinkle with pecans. Bake about 30 minutes until hot & bubbly; cover with foil last 15 minutes to prevent burning. Top with remaining Jack and serve hot.