Prep the Protein & Produce: Cut the chicken into even cubes, pat dry with paper towels, and place in a bowl. Toss with 1 tablespoon of olive oil, minced garlic, oregano, smoked paprika, salt, and pepper. Chop all your vegetables into uniform pieces.
Sauté the Vegetables: Heat 1 tablespoon of olive oil in a large 12-inch skillet over medium-high heat. Add the bell peppers, zucchini, and red onion. Season with a pinch of salt, pepper, and oregano. Sauté for 8-9 minutes until they start to soften and char slightly. Add the cherry tomatoes and cook for 3 more minutes until the skins begin to wrinkle. Transfer the vegetables to a clean plate.
Sear the Chicken: In the same skillet, add another tiny drizzle of olive oil if dry. Add the chicken pieces in a flat, single layer. Allow them to sear undisturbed for 3-4 minutes to build a beautiful golden crust. Toss and cook for an additional 4-5 minutes, ensuring the chicken is cooked through and registers 165°F (74°C).
Combine and Warm: Turn the heat down to medium-low. Return the cooked vegetables and any resting juices back into the skillet with the chicken. Stir gently to combine and let everything warm through together for 1-2 minutes.
Garnish and Serve: Remove from the heat. Pour the fresh lemon juice evenly over the dish. Garnish generously with chopped fresh parsley and crumbled feta if desired. Serve immediately.