Preheat your grill to 400℉ or heat a grill pan over medium-high heat on the stovetop.
In a small bowl, mix all the spices (smoked paprika, salt, cumin, thyme, oregano, onion powder, garlic powder, cayenne, and black pepper) until well combined. Set aside.
If your chicken breasts are thick, slice them in half horizontally or pound them to ½–¾ inch thickness for even cooking.
Pat the chicken dry with a paper towel, then rub or brush each piece with avocado oil. Sprinkle the seasoning mix generously on both sides and rub it in evenly.
Lightly oil your grill grates or grill pan to prevent sticking.
Place the chicken onto the hot grill or pan. Cook for 4-7 minutes on each side, or until the internal temperature registers 165℉. You should see a beautiful “blackened” crust on the outside.
Remove the chicken from the grill and let it rest for at least 5 minutes before slicing and serving.