In a small bowl, combine the garlic powder, oregano, coriander, cumin, smoked paprika, turmeric, salt and pepper. Set aside.
Pat the chicken dry then season both sides of the chicken with 2 tablespoons of the spice mixture, reserving the rest for the rice.
Heat the oil in a large, deep skillet over medium-high heat. When hot, add the chicken in a single layer and cook on both sides until a golden-brown crust forms, 2 to 3 minutes per side. The chicken does not need to be fully cooked yet. Set the browned chicken on a clean plate and set aside.
Reduce the heat to medium. Add the butter and let melt. Add the onions and cook, stirring, until they begin to soften, about 2 minutes.
Add the rice and toss to combine. Stir in the remaining spice mixture and lemon zest. Cook, stirring, to toast the rice and spices, about 2 minutes.
Add the lemon juice, chicken broth, and parsley and stir to combine. Bring to a rapid simmer. Once simmering, reduce the heat to a light simmer and nestle the chicken and any of its juices back into the skillet. Cover and cook, simmering lightly, for 20 minutes. Remove from heat but keep the cover on and allow the rice to steam for another 5 more minutes.