Preheat oven to 350°. In a small bowl, combine salsa and sour cream. Arrange half the tortilla chips in a greased 13x9-in. baking pan. Layer with half the salsa mixture, all of the spinach, half the shredded cheese and half the bacon. Top with remaining tortilla chips, salsa mixture, shredded cheese and bacon., Bake, until dish is heated through and cheese is melted, 20-25 minutes. Meanwhile, heat a large nonstick skillet over medium-high heat. Break eggs, 1 at a time, into pan; reduce heat to low. Cook until whites are set and yolks begin to thicken, turning once if desired., Top chilaquiles with cooked eggs, Cotija cheese, cilantro and, if desired, avocado.