Trim any excess fat from the chicken thighs if desired and pat them dry with paper towels.
Combine the avocado oil, teriyaki sauce (or coconut aminos), and minced garlic in a large zip-top bag or shallow bowl.
Add the chicken thighs to the bag, seal, and move the contents around until each piece is well coated with the marinade.
Refrigerate and marinate at least 1 hour or up to 24 hours for best flavor.
When ready to bake, preheat the oven to 375°F (190°C).
Transfer the marinated chicken and any remaining marinade to a large casserole dish, arranging the thighs in a single layer skin-side up.
Bake at 375°F for 40 minutes.
Increase the oven temperature to 420°F and bake an additional 5 to 10 minutes, or until the skin is crispy and an instant-read thermometer inserted into the thickest part reads 165°F.
Remove from the oven and let rest a few minutes before serving.