Preheat oven to 350 degrees. Place chicken in a lightly greased baking dish; top with garlic, basil, lemon zest and onion.
Nestle broccoli florets around the chicken then pour broth and lemon juice over the top. Cover with foil and bake for 45 minutes or until chicken juices run clear. Carefully remove foil (watch out for steam!) then remove chicken and broccoli from baking dish and keep warm.
Transfer broth mixture from the baking dish to a medium saucepan over medium heat. In a cup, combine cornstarch and water. Whisk almond milk into broth mixture, followed by cornstarch/water mixture. Bring sauce to a boil and cook until thickened.
Serve over chicken and broccoli and enjoy!!