Season the chicken breast evenly with sea salt, black pepper, and garlic powder.
Heat the olive oil in a skillet over medium-high heat and sear the chicken until golden and cooked through, approximately 6 to 7 minutes per side.
While the chicken is cooking, steam or lightly sauté the broccoli, bell peppers, and zucchini until they are tender-crisp.
In a small mixing bowl, whisk together the tahini and lemon juice, adding a teaspoon of water at a time until a smooth, pourable consistency is reached.
Once the chicken is finished, let it rest for 2 minutes before slicing it into thin strips.
Assemble the power bowl by placing the cooked quinoa at the base and topping it with the sautéed vegetables and sliced chicken.
Drizzle the lemon-tahini sauce over the entire bowl and serve immediately.