Poach chicken breasts in cold water (just enough to cover) with onion, salt, peppercorns, or any aromatics.
Once the water boils, reduce heat and cook for 10 to 15 minutes until chicken reaches 165°F internally.
Shred the chicken (shred in stand mixer)
Preheat oven to 350 degrees.
In a skillet, sauté diced onion and celery in butter until softened, then stir in shredded chicken.
Whisk together cream of chicken soup, diced green chiles, and sour cream.
Butter or spray a casserole dish and spread a thin layer of the mixture across the bottom.
Fill tortillas, roll them up, and place seam-side down in the pan.
Spread the remaining sauce over the top and smother with shredded Monterey Jack cheese.
Bake for 30 minutes at 350°F until bubbly and golden on top.
Let it rest for a few minutes before serving.
