In a medium bowl, combine the garlic powder, coriander, cumin, ginger, salt, and cayenne with a fork. Dredge each piece of chicken in the spices and set aside.
Heat the oil in a skillet over medium heat. Add the chicken, sprinkle any remaining spices on top, and sear for a couple of minutes until golden brown on both sides.
Add the coconut milk and tomato sauce to the pan, bring to a boil, cover with a lid, reduce the heat to low, and cook until the chicken is done all the way through (no longer pink), about 8 - 10 minutes.
Layer in bowls with brown rice on the bottom, then spinach, chicken, sauce, yogurt, and fresh herbs. Enjoy!