Preheat oven to 375°F and cut the corn tortilla into small triangles.
Arrange tortilla triangles on a baking sheet and bake for 8 to 10 minutes until they are golden and crispy.
Poach or pan-sear the chicken breast until fully cooked, then use two forks to shred it into bite-sized pieces.
In a medium skillet over medium heat, sauté the diced white onion and minced garlic until they become soft and translucent.
Stir in the tomato puree, chipotle powder, sea salt, and black pepper, then let the sauce simmer for about 5 minutes to develop flavor.
Gently fold the shredded chicken and baked tortilla chips into the sauce until they are well-coated and the chips have slightly softened.
In a separate small non-stick skillet, heat the avocado oil and fry the egg until the whites are set but the yolk remains runny.
Transfer the chilaquiles to a plate and top with the fried egg, sliced avocado, crumbled cotija cheese, and fresh cilantro.