Preheat your oven to 375°F (190°C).
Season the chicken breast with a pinch of salt and pepper, then poach or pan-sear until fully cooked and shred it using two forks.
Heat the avocado oil in a skillet over medium heat and sauté the diced yellow onion and minced garlic until they become soft and translucent.
Add the shredded chicken, ground cumin, chili powder, sea salt, and black pepper to the skillet, stirring well to incorporate all the flavors.
Lightly toast the corn tortillas in a dry pan for about 30 seconds per side until they are warm and pliable.
Pour a small amount of the red enchilada sauce into the bottom of a baking dish to prevent sticking.
Place a portion of the chicken mixture into each tortilla, roll them up tightly, and arrange them seam-side down in the prepared baking dish.
Pour the remaining red enchilada sauce over the top of the tortillas and sprinkle evenly with the shredded Monterey Jack cheese.
Bake for 15 to 20 minutes until the sauce is bubbling and the cheese has melted into a golden layer.
Serve the enchiladas warm, topped with a dollop of plain Greek yogurt and a garnish of fresh cilantro.