In a bowl, whisk together balsamic vinegar, honey, minced garlic, Dijon mustard, thyme, salt, and pepper. Reserve 1/4 cup of this marinade for glazing later. Add chicken thighs to the remaining marinade, cover, and refrigerate for at least 30 minutes, preferably 2 hours for more flavor.
Preheat your oven to 400°F (200°C).
In an oven-safe skillet, heat olive oil over medium-high heat. Remove the chicken from the marinade, letting excess drip off. Place the chicken thighs skin side down in the skillet and sear for about 5-7 minutes until the skin is golden brown.
Flip the chicken thighs over and add the sliced zucchini, bell pepper, and cherry tomatoes around the chicken in the skillet.
Pour the reserved balsamic marinade over the chicken and vegetables.
Transfer the skillet to the preheated oven and bake for about 25-30 minutes or until the chicken is cooked through and reaches an internal temperature of 165°F (75°C).
For crispy skin, switch the oven to broil mode and broil for an additional 3-5 minutes, watching closely to avoid burning.
Remove from the oven and let the chicken rest for 5 minutes. Serve the chicken thighs with the glazed vegetables and spoon any remaining sauce over the top.
Notes
For best flavor, marinate the chicken for at least 2 hours.