Preheat the oven to broil. Make sure the oven rack is in the middle. If it's too high, the chicken will burn.
Grease the bottom of a 9x9 casserole dish. Place chicken thighs skin side up in the casserole dish.
Combine the avocado oil, salt, pepper, garlic and lemon juice in a small bowl. Brush the chicken thighs with the oil mixture, saving some for basting.
Broil for about 22-24 minutes, flipping around the 7-8 minute mark and again at the 13-14 minute mark. Baste with the oil mixture after turning. Remove from the oven when the chicken reaches 165° degrees. Let the chicken rest about 5 minutes before serving. Garnish with parsley.