01 - Set the oven to 400°F.
02 - Wash zucchinis and slice each in half lengthwise. Scoop out the flesh using a spoon, leaving a 1/4-inch thick shell. Finely chop the reserved zucchini flesh.
03 - Heat olive oil in a large skillet over medium heat. Add chopped onion and cook until translucent, approximately 3 minutes. Add minced garlic and cook for an additional minute.
04 - Add chopped zucchini flesh and diced cherry tomatoes to the skillet. Sauté for 3 to 4 minutes until softened.
05 - Incorporate cooked chicken, dried Italian herbs, salt, and pepper into the skillet. Cook for 2 minutes, then remove from heat and allow to cool slightly.
06 - Stir in half of the mozzarella and all the Parmesan cheese into the chicken mixture.
07 - Place zucchini shells in a baking dish and evenly fill each with the chicken mixture. Top with the remaining mozzarella cheese.
08 - Bake in the preheated oven for 20 to 25 minutes until the zucchinis are tender and the cheese is melted and golden.
09 - Sprinkle freshly chopped parsley over the baked zucchini boats before serving.