Preheat your grill or stovetop grill pan over medium-high heat.
In a bowl, whisk together 3 tablespoons of olive oil, lemon juice, minced garlic, oregano, basil, thyme, salt, and black pepper.
Coat the chicken breasts with the herb marinade and let them sit for 10 minutes to absorb the flavors.
Grill the chicken for about 10 minutes on each side, or until the internal temperature reaches 165°F (74°C) and the juices run clear.
While the chicken is grilling, prepare the salad by combining mixed greens, cherry tomatoes, cucumber slices, red onion, feta cheese, and Kalamata olives in a large salad bowl.
Once the chicken is cooked, let it rest for a few minutes, then slice it into strips.
Top the salad with the grilled chicken slices.
Drizzle the remaining 2 tablespoons of olive oil over the salad and garnish with lemon zest.
Toss the salad gently to mix the ingredients and coat everything with the dressing.
Serve immediately, or chill in the refrigerator if preferred.