Combine gf tamari sauce, stevia, and gf flour in a small bowl and stir until smooth. Add garlic, and pour over chicken to marinate. Cover and refrigerate for 15 minutes.
Heat oil over a medium high heat in your wok or large skillet. Add broccoli, carrots, and onion.
Cook and stir until tender, about 5 minutes. Remove vegetables and set aside.
Remove chicken from marinade, reserving marinade.
Heat 1 more tablespoon of oil in wok over medium-high heat. Cook and stir chicken, about 2 minutes per side. Bite-size pieces of chicken cook very quickly.
Return vegetables and reserved marinade and bring to a boil.
Continue to cook about 5 more minutes. Serve over rice.