Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch cubes and halve any larger baby potatoes so they cook evenly.
Place the chicken, potatoes, and broccoli florets onto the prepared sheet pan.
In a small glass jar or bowl, whisk together the olive oil, lemon juice, oregano, garlic powder, salt, and pepper.
Pour the lemon-herb dressing over the chicken and vegetables, tossing thoroughly with your hands to ensure every piece is coated.
Arrange the ingredients in a single, even layer, ensuring the chicken pieces aren't touching for maximum browning.
Roast for 22-25 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender.
Remove from the oven and sprinkle with fresh lemon zest to awaken the flavors before serving.