Pat dry chicken thighs and dice into bite size cubes. Add salt, black pepper and garlic powder. Toss together making sure chicken is well seasoned.
In a large cast iron skillet, drizzle oil and place on stovetop. Turn stove on medium-high heat and bring skillet to a heat. Toss chicken on heated skillet and sauté until chicken is cooked through and reaches a golden-brown shade. Cook in batches if you have to. Turn heat off and set browned chicken to the side.
In a small mixing bowl, whisk together ingredients for Teriyaki sauce; water, coconut aminos, honey, ginger, garlic, and coconut sugar. Once ingredients are well combined pour into a small sauce pan. Place sauce pan on stovetop and bring to a light simmer on low heat. Continue to simmer for about 5 minutes.
While teriyaki sauce simmers, make slurry by stirring water and arrowroot flour together in a small bowl. Turn heat off and add slurry to sauce. Keep stirring as it gets thick. It should start thickening immediately.
Pour teriyaki sauce over cooked chicken. Give it a good toss making sure the chicken is well coated with the sauce. Serve immediately over rice or cauliflower rice and broccoli. Make sure to serve before it gets cold. Enjoy!