For the Chicken:

1. In a bowl, whisk together olive oil, lemon juice, dried oregano, garlic powder, onion powder, paprika, salt, and black pepper.
2. Place the chicken breasts or thighs in a resealable plastic bag or shallow dish and pour the marinade over the chicken.
3. Seal the bag or cover the dish and refrigerate for at least 30 minutes, preferably 2-3 hours, to allow the flavors to infuse.
4. Preheat the grill or a skillet over medium-high heat. Grill or cook the chicken for 6-7 minutes per side, or until the internal temperature reaches 165°F (75°C) and the chicken is fully cooked.
5. Once cooked, remove the chicken from the heat and let it rest for 5 minutes before slicing. Garnish with chopped fresh parsley.

For the Lemon Rice:

1. In a medium saucepan, heat olive oil (or butter) over medium heat. Add the rice and cook for 2 minutes, stirring occasionally to toast it slightly.
2. Add the chicken broth (or water), lemon zest, lemon juice, salt, and black pepper. Stir to combine.
3. Bring the mixture to a boil, then reduce the heat to low, cover, and simmer for 15-20 minutes, or until the rice is tender and the liquid has been absorbed.
4. Remove the saucepan from the heat and let the rice sit, covered, for 5 minutes before fluffing with a fork.
5. Stir in the fresh parsley and adjust seasoning with more lemon juice or salt if desired.

To Serve:

1. Serve the sliced Greek chicken over a bed of lemon rice. Garnish with extra parsley and optional crumbled feta cheese.