Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Dice the Yukon Gold potato into small 1/2-inch cubes to ensure they roast at the same rate as the proteins.
Arrange the chicken breast, salmon fillet, and potato cubes on the prepared sheet pan in a single layer.
In a small bowl, whisk together the olive oil, lemon juice, oregano, garlic powder, sea salt, and black pepper.
Drizzle the herb oil over the chicken, salmon, and potatoes, tossing the potatoes slightly to coat all sides.
Roast in the oven for 15-18 minutes, or until the chicken reaches an internal temperature of 165°F and the salmon flakes easily with a fork.
While the sheet pan is roasting, steam the broccoli florets in a steamer basket over boiling water for 4-5 minutes until bright green.
Assemble your meal prep container or plate by layering the cooked brown rice, steamed broccoli, roasted potatoes, chicken, and salmon.