Heat the oven to 375°F. Line a baking sheet with parchment paper.
In a large bowl, combine the ground turkey, egg, breadcrumbs, ¼ cup of the pesto, 2 tablespoons of the Parmesan, salt, and pepper. Mix gently until just combined. Shape the mixture into a compact loaf on the prepared baking sheet.
Bake the meatloaf until cooked through and the center reaches 165°F, about 40 to 45 minutes. Let it rest for 5 minutes before slicing.
While the meatloaf bakes, bring the chicken broth to a boil in a small saucepan. Stir in the couscous, cover the pan, and remove it from the heat. Let it stand for 5 minutes, then fluff with a fork and stir in the remaining 2 tablespoons of Parmesan.
Heat the olive oil in a large skillet over medium heat. Add the zucchini and cook, stirring occasionally, until tender with lightly browned edges, about 7 to 9 minutes.
Slice the meatloaf and serve it with the Parmesan couscous and zucchini. Spoon the remaining pesto over the meatloaf or serve it alongside.