Preheat your oven to 375°F. Cut the corn tortillas into triangles, spread them on a baking sheet, and bake for 10-12 minutes until crispy and golden.
Heat the olive oil in a medium skillet over medium heat. Add the diced onion and minced garlic, sautéing until fragrant and translucent.
Stir in the tomato puree, minced chipotle in adobo, sea salt, and black pepper. Let the sauce simmer for about 5 minutes to allow flavors to meld.
Add the shredded cooked chicken to the sauce, stirring to ensure it is heated through.
Gently fold the baked tortilla chips into the sauce until they are well coated but still retain some of their crunch.
In a separate small non-stick skillet, fry the egg to your preference, ideally sunny-side up or over-easy so the yolk remains runny.
Transfer the chilaquiles to a plate, top with the fried egg, and garnish with crumbled Cotija cheese, sliced radishes, and fresh cilantro.