Add the chicken thighs, garlic, ginger, salt, black pepper, and red pepper flakes to a small bowl and stir until well combined.
Heat a large skillet over medium-high heat. Once hot, coat the pan with oil and then add in the chicken. Cook the chicken for 6-8 minutes until browned and cooked through. Once cooked, remove the chicken from pan and set aside.
While the chicken is cooking, make the sauce. Add the coconut aminos, fish sauce, sesame oil and arrowroot starch to a small bowl and whisk until well combined.
Next, add in the broccoli florets and ⅓ cup of water. Cook the broccoli until it is bright green and slightly tender, around 4-6 minutes.
Next, add the chicken back to the skillet and then add the sauce. Give everything a stir to combine chicken, broccoli, and sauce are all well combined and cook for one more minute. The sauce should thicken a bit as it heats.
Remove the skillet from the heat, finish with sliced green onions and sesame seeds, and then serve the stir-fry immediately. Enjoy!