Preheat the oven to 400 degrees F. Lightly butter an 8 by 8-inch baking dish.
Cook the gnocchi according to package directions.
In a large deep saute pan over medium-high heat, add the oil. Stir in the garlic and red pepper flakes and cook until the garlic begins to brown, about 1 to 2 minutes. Add the tomatoes, salt, pepper, and parsley. Reduce the heat and bring to a simmer. Add the gnocchi and chicken. Toss well to combine. Mix in the mozzarella and 2 tablespoons of the Parmesan. Pour the mixture into the baking dish and sprinkle with the remaining Parmesan. Bake until the cheese is melted and nicely browned, about 15 to 20 minutes. Remove the dish from the oven, garnish with the basil leaves and serve.