Layered Chicken Three-Cheese Enchilada

INGREDIENTS

• 1 Tbs. olive oil
• 1 yellow onion, cut into 1/2-inch dice
• Kosher salt and freshly ground pepper, to taste
• 1 1/4 lb. boneless, skinless chicken breasts, cooked and shredded
• 1 3/4 cups red enchilada sauce
• 9 corn tortillas, each about 6 inches in diameter
• 3/4 cup shredded mozzarella cheese
• 3/4 cup shredded white cheddar cheese
• 3/4 cup shredded yellow cheddar cheese
• Sliced green onion tops for garnish
• Chopped fresh cilantro for garnish