Preheat your oven to 400°F (200°C) and line three large sheet pans with parchment paper to ensure even roasting and easy cleanup.
In a very large mixing bowl, whisk together the extra virgin olive oil, fresh lemon juice, lemon zest, minced garlic, dried oregano, sea salt, and black pepper until well combined.
Add the 2.63 lbs of thinly sliced chicken breast and the 16 cups of broccoli florets to the bowl, tossing thoroughly with your hands or tongs until every piece is evenly coated in the marinade.
Spread the chicken and broccoli across the prepared sheet pans in a single layer, making sure the pieces are not overlapping to prevent steaming and encourage browning.
Roast in the oven for 15 to 18 minutes, rotating the pans halfway through, until the chicken reaches an internal temperature of 165°F and the broccoli edges are slightly charred and tender.
Remove from the oven and let the chicken rest on the pans for 3 minutes to allow the juices to redistribute through the thin slices.
For precise meal prep, divide the entire batch into 8 equal servings; each portion should weigh approximately 4 oz of cooked chicken and 6.5 oz of roasted broccoli.