In a bowl, combine the olive oil, lemon juice, mixed herbs, salt, and pepper to create the marinade.
Place the chicken breast in a resealable bag or shallow dish and pour the marinade over it, ensuring it is well coated. Marinate for at least 30 minutes in the refrigerator.
While marinating, cook the quinoa according to package instructions.
Chop the broccoli into small florets, slice the red bell pepper, and peel and julienne the carrot.
Preheat a grill pan or skillet over medium-high heat. Grill the marinated chicken for about 6-7 minutes per side, or until fully cooked and internal temperature reaches 165°F.
In a separate pan or using steamed method, lightly sauté or steam the vegetables until tender but still crisp.
Slice the grilled chicken and assemble the bowl by layering the cooked quinoa, fresh vegetables, and chicken slices.
Drizzle any remaining marinade over the bowl if desired, and season with additional salt and pepper to taste before serving.