Bring a large saucepan of salted water to a boil over high heat. Add the butternut squash cubes and cook until tender when pierced with a fork, about 10 minutes. Using a slotted spoon, transfer the squash to a bowl and mash with the back of a fork. Set aside.
Add the tortellini to the boiling water and cook for 2 minutes less than directed by package instructions. Drain the tortellini and transfer to a large bowl.
To the tortellini, add 1 cup tomato sauce, mashed butternut squash, turkey (or chicken) and chard. Stir to combine.
Spread ¾ cup tomato sauce on the bottom of a 9- by 12-inch (or 9- by 13 inch) baking dish.
Transfer half or the tortellini mixture to the baking dish and spread evenly. Top with ¾ cup tomato sauce.
Transfer the remaining tortellini mixture to the baking dish, spreading evenly. Spread remaining ¾ cup tomato sauce over top.
Sprinkle the topping evenly on top of the tortellini. Bake, uncovered, until the cheese is melted and the casserole is heated through, about 30 minutes. Serve.
The Topping:
In a medium bowl, stir together the Parmesan cheese, sage and pecans.