Preheat your grill or grill pan over medium-high heat. While it heats, season the chicken breasts with olive oil, garlic powder, onion powder, salt, and pepper.

Once the grill is hot, add the chicken breasts and cook for about 6-7 minutes on each side, or until the internal temperature reaches 165°F. Remove from the grill and let rest for 5 minutes before slicing.

While the chicken is resting, steam the broccoli florets until tender, about 4-5 minutes.

In a small bowl, mix together the Greek yogurt, mayonnaise, minced garlic, lemon juice, and a pinch of salt and pepper to create the creamy garlic sauce.

To assemble the bowls, divide the cooked brown rice or quinoa among four bowls. Top each with sliced grilled chicken, steamed broccoli, and a generous drizzle of the creamy garlic sauce.

Garnish with fresh parsley if desired. Serve immediately.