In a medium bowl, whisk together the olive oil, soy sauce, balsamic vinegar, lemon juice, brown sugar, Dijon mustard, and all dried herbs until fully combined.

Slice the zucchini, bell peppers, and red onion into uniform pieces and toss in reserved marinade for 30 minutes.

Cut the chicken breasts into cubes and mix with remaining marinade in a zip-top bag. Refrigerate for at least 4 hours or overnight.

If using wooden skewers, soak them in water for 30 minutes. Preheat your grill or oven.

Thread the chicken pieces and marinated vegetables onto the skewers.

For grilling, preheat grill to medium-high and grill for 8-12 minutes, basting with reserved marinade.

For baking, preheat oven to 400°F and bake for 16-22 minutes.

Let the kabobs rest for 5-10 minutes before serving.