In a small bowl, mix together the olive oil, lemon juice, garlic powder, salt, and black pepper. Stir well and set aside.
Slice the avocado and cucumber. Cut the cherry tomatoes in half. Wash and drain the mixed greens or lettuce if needed.
Place the cooked rice or quinoa into a serving bowl. If desired, warm it in the microwave for 1–2 minutes.
Arrange the mixed greens or lettuce on one side of the bowl over the rice or quinoa.
Place the sliced avocado, cherry tomatoes, and cucumber around the bowl.
Add the chicken.
Top the bowl with the cooked and sliced chicken breasts.
Pour the prepared dressing evenly over the chicken, vegetables, and rice or quinoa.