In a large bowl, season the boneless, skinless chicken breasts generously with salt and black pepper.

Heat 2 tablespoons of olive oil in a large skillet over medium heat. Add the chopped red onion and red bell pepper, cooking until softened, about 5 to 7 minutes. Stir in the minced garlic and cook for another minute.

Add the seasoned chicken breasts to the skillet with the sautéed vegetables. Cook for 5 to 7 minutes, turning occasionally, until evenly browned.

Stir in the diced tomatoes, sun-dried tomatoes, kalamata olives, and dried oregano, basil, and thyme. Bring to a simmer, cover, and cook for 15 to 20 minutes.

Remove from heat and gently fold in crumbled feta cheese, allowing it to melt slightly into the sauce.

Serve over a bed of cooked quinoa or couscous and garnish with freshly chopped herbs.