Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Dice the potato into small half-inch cubes to ensure they cook through at the same rate as the vegetables.
In a large bowl, toss the potato cubes with half of the olive oil, sea salt, and black pepper.
Spread the potatoes on the baking sheet and roast for 15 minutes until they begin to soften.
While potatoes roast, slice the zucchini and yellow squash into half-moons and mince the garlic.
Season the chicken breast with the dried oregano, minced garlic, and the remaining salt and pepper.
Remove the tray from the oven, add the chicken, zucchini, and squash, then drizzle with the remaining olive oil and lemon juice.
Return the tray to the oven and roast for an additional 18 to 20 minutes until the chicken reaches an internal temperature of 165°F and the potatoes are golden.