Heat oil in a large skillet over medium heat.
Fry the tortilla pieces until golden brown and crispy, about 3-5 minutes.
Remove the tortillas and drain on paper towels.
In the same skillet, add the salsa and bring to a simmer.
Add the crispy tortillas to the salsa and stir to coat evenly.
If using, add the shredded chicken to the pan and mix well.
Cook for an additional 2-3 minutes until heated through.
Remove from heat and transfer the mixture to a serving dish.
Top with crumbled queso fresco, avocado slices, and cilantro.
Serve with sour cream and lime wedges on the side.