How to Make It
Preheat oven to 350°F. Cook shell pasta according to package directions; drain and cover to keep warm.
While pasta cooks, heat olive oil in a large skillet over medium. Add onion, and cook, stirring often, until translucent, about 3 minutes. Add minced garlic, and cook, stirring constantly, until fragrant, about 30 seconds. Add ground turkey, and cook, stirring often, until turkey is browned and cooked through, about 5 minutes. Working in batches, add chopped Swiss chard and cook, stirring constantly, until wilted, about 2 minutes. Sprinkle mixture with salt and pepper. Stir in marinara sauce, and bring mixture to a boil. Remove from heat, and add 1/4 cup of the chopped fresh basil. Stir to combine.
Stir together pasta and marinara mixture in a lightly greased 13- x 9-inch baking dish until combined. Top mixture with shredded mozzarella, and bake in preheated oven until cheese is melted, about 5 to 7 minutes. Sprinkle with remaining 1/4 cup fresh basil leaves, and serve hot.