Preheat the oven to 400°F (200°C).
Cut the chicken breasts into 1-inch pieces and place in a large mixing bowl.
Add the chopped bell pepper, onion, artichoke hearts, spinach, and parmesan cheese (if using) to the bowl.
In a separate small bowl, stir together mayonnaise, minced garlic, lemon zest and juice, oregano, thyme, salt, and pepper.
Pour the dressing over the chicken and veggies and gently stir until well combined.
Transfer the mixture into a 9x13-inch baking pan.
Bake uncovered for 25 to 30 minutes or until the chicken is cooked through.
Remove from the oven and serve, optionally spooning some of the accumulated juices over rice or lentils.