Pat the chicken breast dry with paper towels. In a small bowl, mix dried thyme, dried rosemary, salt, and black pepper.
Lightly coat the chicken breast with the herb mixture, pressing gently to adhere.
Preheat a cast iron or non-stick skillet over medium-high heat with olive oil.
Place the chicken breast in the pan and sear for about 4-5 minutes on each side until a golden crust forms and the chicken is cooked through (internal temperature of 165°F).
While the chicken cooks, chop the mixed bell peppers, zucchini, and red onion into bite-sized pieces.
After searing the chicken, remove it from the pan and set aside. In the same pan (or in a separate baking sheet if you prefer oven roasting), toss the vegetables with a drizzle of olive oil, salt, and pepper.
Roast or sauté the vegetables on medium heat for about 6-8 minutes until they are tender yet crisp, stirring occasionally.
Plate the herb-crusted chicken breast alongside the roasted vegetables and serve immediately.