In a mason jar, combine coconut aminos, water, garlic, arrowroot starch, 1 tablespoon sesame oil, ginger, red pepper flakes, and fish sauce. Shake vigorously to combine. Store the Teriyaki sauce in the refrigerator for up to 2 weeks.

Rinse and pat the chicken very dry with paper towel. Add it to a bowl and pour in the teriyaki sauce. Toss to coat, cover with a lid or plastic wrap, and marinate in the fridge for 1-4 hours.

Meanwhile, preheat a large sauté pan or wok over medium heat for 5 minutes. Add the avocado oil and heat until shimmering. Raise the heat to high and add the cabbage, carrot and white parts of the green onion. Cook, stirring, until the cabbage has softened slightly, around 5 minutes. Add the bean sprouts, 2 tablespoons coconut aminos and 1 tablespoon sesame oil. Cook, stirring, until the sauce has reduced by ¼ in volume, around 3 minutes. Taste for seasoning and adjust with salt and pepper as desired. Cover and set aside.

Preheat your Traeger grill to 475F. Place the chicken thighs along the front or back perimeter where the grill is hottest. If using a gas or propane grill, cook the chicken over direct, medium-high heat. Pour the reserved marinade into a sauce pan along with ¼ cup water. Stir to combine and place onto the grill. Cook the chicken until grill marks form, around 6 minutes. Flip, brush with the teriyaki glaze, and cook until the thickest parts of the thighs reach at least 165F internal. Transfer to a serving platter and garnish with sesame seeds and the green parts of the green onion. Serve with the stir-fried cabbage.