Preheat your oven to 375°F.
In a small skillet, heat the olive oil over medium heat and sauté the diced red onion until it becomes soft and translucent.
Add the tomato sauce, chili powder, ground cumin, and garlic powder to the skillet, stirring well and simmering for 5 minutes until the sauce thickens slightly.
In a medium mixing bowl, combine the shredded cooked chicken breast with 2 tablespoons of the prepared red chili sauce, sea salt, and black pepper.
Briefly warm the corn tortillas in a dry pan over medium heat for 30 seconds per side until they are pliable and easy to roll.
Place a portion of the chicken mixture into the center of each tortilla, roll them up tightly, and arrange them seam-side down in a small oven-safe baking dish.
Pour the remaining red chili sauce evenly over the top of the rolled tortillas and sprinkle with the shredded sharp cheddar cheese.
Bake in the preheated oven for 15 minutes, or until the cheese is melted and bubbly and the edges of the tortillas are slightly crisp.
Remove from the oven and garnish with fresh chopped cilantro before serving hot.