Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Dice the chicken breast into 1-inch cubes and chop the broccoli and red bell pepper into uniform, bite-sized pieces.
Place the chicken, broccoli, and bell pepper on the prepared baking sheet, then drizzle with olive oil.
Sprinkle the sea salt, black pepper, and garlic powder over the mixture and toss thoroughly to ensure everything is evenly coated.
Roast in the center of the oven for 18-20 minutes until the chicken is cooked through and the vegetables are tender with slightly charred edges.
While the vegetables roast, place the sliced almonds in a small dry skillet over medium heat, tossing frequently for 2-3 minutes until golden and fragrant.
In a large mixing bowl, combine the roasted chicken and vegetable mixture with the cooked quinoa and toasted almonds.
Drizzle the fresh lemon juice over the bowl and toss one last time to brighten the flavors before serving.