Heat oven to 400º F. In a small bowl, combine the ricotta, half the spinach (reserve the rest for another use), salt, and pepper and mix well. In another bowl, stir the squash, sour cream, and nutmeg together. In a skillet, over medium heat, heat the butter. Add the sage and cook until fragrant, about 1 minute. Add the broth, simmer 5 minutes, and set aside. Lay out 16 wonton wrappers. Divide the spinach mixture among 8 wrappers, placing a dollop in the center of each. Fold them in half diagonally, pinching one corner to close. Repeat with the squash mixture and the remaining 8 wrappers. Place the 16 packets in a roasting pan and spoon the broth over them. Cover with foil and heat in the oven until warmed through, 10 to 15 minutes.