In a small bowl, whisk together the sweetener, sea salt, all spice, pepper, garlic, cayenne, parsley, paprika, thyme, cinnamon, and nutmeg. Rub the chicken all over with the spice blend.
In a large skillet over medium heat, heat the avocado oil until shimmering. Add the chicken skin-side down and do not disturb for 4 minutes, until the skin is golden brown. Flip the chicken and cook another 4 minutes.
Remove the chicken to a plate and add the onion to the pan. Sauté until translucent, about 4 minutes. Add the cauliflower rice and cook until just tender, another 4 minutes.
Return the chicken thighs to the pan, skin-side up, and transfer the whole skillet to the oven. Bake 20 minutes or until the chicken reaches an internal temperature of 165ºF.