Preheat oven to 350F.
Finely chop and set aside ¾ chopped onion. Store ¼ for garnish.
Cut chicken into bite sized pieces.
In a large sauté pan over medium heat, add 1T olive oil, chopped chicken, chopped red onion, ¼ tsp salt, 1/8 tsp pepper and 4 oz green chiles and sauté until chicken is fully cooked.
In the center of corn tortilla, add ~2T chicken/chili mixture and 1T shredded cheese (optional). Roll tightly. Repeat 7 times.
Spread ¼ cup enchilada sauce on the bottom of a 9x13 baking pan.
Place each enchilada seam side down on top of enchilada sauce.
Top with remaining enchilada sauce and spread until they’re completely coated with sauce.
Bake uncovered, ~20 mins.
Slice one avocado. Garnish w/ remaining red onions and sliced avocado.