Start by cooking the brown rice according to package instructions. Once cooked, set aside and keep warm.

In a bowl, mix olive oil, garlic powder, onion powder, oregano, paprika, salt, and pepper to create a marinade.

Coat the chicken breasts with the marinade and let them sit for at least 15 minutes to absorb the flavors.

Heat a grill pan or skillet over medium-high heat. Cook the marinated chicken for about 6-7 minutes per side, or until the internal temperature reaches 165°F. Remove from heat and let rest for 5 minutes before slicing.

In a large bowl, combine the cherry tomatoes, cucumber, red onion, feta cheese, olives, and parsley. Drizzle with lemon juice and toss gently to combine.

To assemble the bowls, divide the cooked brown rice among serving bowls, top with sliced chicken, and add the vegetable mixture on the side.