Pat the chicken breast dry and cut it into bite-sized 1-inch cubes.
Chop the zucchini, red bell pepper, and broccoli into uniform pieces to ensure even cooking.
Heat the extra virgin olive oil in a large cast-iron skillet over medium-high heat.
Add the chicken cubes to the skillet, seasoning with half of the salt, pepper, and oregano.
Sear the chicken for 5-6 minutes until golden brown and cooked through, then remove from the pan and set aside.
In the same skillet, add the broccoli, zucchini, and bell pepper, sautéing for 4-5 minutes until tender-crisp.
Stir in the minced garlic and cook for 30 seconds until fragrant.
Return the chicken to the pan, drizzle with fresh lemon juice, and sprinkle with the remaining seasonings.
Toss everything together for one minute to meld the flavors and serve immediately.