Preheat your oven to 375°F (190°C).
Season the chicken breast with sea salt and black pepper, then poach in simmering water for 12-15 minutes until cooked through.
Remove the chicken from the water and use two forks to shred it into fine pieces.
Heat the avocado oil in a small skillet over medium heat and sauté the diced onions and bell peppers until they are soft and slightly caramelized.
In a mixing bowl, combine the shredded chicken, sautéed vegetables, and 2 tablespoons of the red enchilada sauce.
Lightly toast the corn tortillas in a dry pan for 30 seconds per side to ensure they are pliable and won't crack when rolled.
Dip each tortilla into the remaining enchilada sauce, place a portion of the chicken mixture in the center, and roll tightly.
Arrange the rolled tortillas seam-side down in a small baking dish, pour the remaining sauce over the top, and sprinkle with the Monterey Jack cheese.
Bake for 15 minutes until the sauce is bubbling and the cheese has completely melted.
Garnish with fresh cilantro before serving.