Slice the chicken breast into even 1-inch cubes and chop the zucchini and red bell pepper into bite-sized pieces.
Heat a large non-stick skillet over medium-high heat and add the avocado oil, swirling to coat the pan surface.
Add the chicken pieces to the skillet and season with garlic powder, dried oregano, sea salt, and black pepper.
Sauté the chicken for 5 to 6 minutes until golden brown on all sides and nearly cooked through.
Toss in the zucchini and red bell pepper, continuing to cook for another 3 to 4 minutes until the vegetables are tender-crisp.
While the mixture cooks, warm the pre-cooked white rice in a small bowl using the stovetop or microwave.
Drizzle the fresh lemon juice over the chicken and vegetables in the pan, stirring to deglaze and coat everything in the citrus.
Spoon the warm rice into a bowl, top with the lemon-herb chicken and vegetable mixture, and garnish with fresh parsley.