Rinse the quinoa thoroughly in a fine-mesh sieve and combine with 0.5 cup of water in a small saucepan.
Bring the water to a boil, then reduce heat to low, cover, and simmer for 15 minutes until the water is fully absorbed.
Preheat your oven to 400°F and line a baking sheet with parchment paper.
Toss the broccoli florets with 0.5 tsp of the olive oil, 0.125 tsp of the sea salt, and 0.125 tsp of the black pepper.
Roast the broccoli for 15-20 minutes until the edges are golden-brown and slightly crisp.
Season the chicken breast evenly on both sides with the garlic powder, dried oregano, and the remaining salt and pepper.
Heat the remaining 0.5 tsp of olive oil in a non-stick skillet over medium-high heat.
Sear the chicken breast for 6-7 minutes per side until the exterior is golden and the internal temperature reaches 165°F.
Turn off the heat and add the lemon juice and lemon zest to the skillet, swirling the pan to coat the chicken in the bright citrus sauce.
Fluff the cooked quinoa with a fork and serve it topped with the roasted broccoli and the sliced lemon-herb chicken.