Preheat your oven to 400 degrees Fahrenheit and line a large sheet pan with parchment paper.
Cut the chicken breast into bite-sized 1-inch cubes and place them in a large mixing bowl.
Chop the zucchini into half-moons, slice the bell pepper into strips, and mince the garlic cloves.
Add the broccoli, zucchini, and bell pepper to the bowl with the chicken.
In a small jar or bowl, whisk together the olive oil, lemon juice, minced garlic, oregano, sea salt, and black pepper.
Pour the marinade over the chicken and vegetables, tossing thoroughly to ensure every piece is evenly coated.
Spread the mixture in a single layer on the prepared sheet pan, ensuring there is enough space for the air to circulate.
Roast for 18 to 22 minutes, or until the chicken is cooked through and the vegetables are tender and slightly caramelized at the edges.
Remove from the oven and let rest for 2 minutes before serving warm.