1. 1. Prepare the Chicken: Pat the chicken breasts or thighs dry with paper towels. Season generously with salt, pepper, and 1 teaspoon of the dried oregano.

2. 2. Saute the Aromatics: Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Add the sliced red onion and cook for 3-4 minutes until it starts to soften. Add the minced garlic and cook for another minute until fragrant.

3. 3. Cook the Chicken: Push the onion and garlic to one side of the skillet. Add the remaining 1 tablespoon of olive oil to the empty side. Place the seasoned chicken into the skillet and cook for 5-7 minutes per side, or until golden brown and cooked through. The internal temperature should reach 165 F (74 C).

4. 4. Add the Vegetables: Once the chicken is cooked, remove it from the skillet and set aside on a cutting board. Add the sliced bell pepper, cherry tomatoes, and Kalamata olives to the skillet with the remaining oregano. Saute for 5-7 minutes, stirring occasionally, until the bell pepper is slightly tender-crisp and the tomatoes begin to burst.

5. 5. Combine and Finish: Slice the cooked chicken into strips or bite-sized pieces. Return the chicken to the skillet with the vegetables. Squeeze the fresh lemon juice over everything and toss gently to combine all the flavors.

6. 6. Garnish and Serve: Stir in the fresh chopped parsley. Taste and adjust seasoning if needed. Serve immediately over a bed of cooked quinoa or brown rice, topped with crumbled feta cheese if desired.