Bring a large pot of lightly salted water to a boil and add pasta. Cook until al dente. When done cooking, drain.
While pasta is cooking, heat olive oil in a large skillet over medium heat and add in sliced onion. Cook for about 10 minutes, until tender. Add the garlic, sausage, and sage to skillet.
Combine pumpkin and cottage cheese in a blender or food processor and blend until very smooth.
Once chicken sausage is heated through, add pumpkin and cottage cheese mixture to skillet, along with the spinach. Stir in salt, pepper, and nutmeg and cook over low heat to warm sauce.
Add pasta to the skillet and toss everything together. If your skillet isn't large enough, you can toss everything together in a separate large bowl. return it to the pot.
Top pasta with crumbled goat cheese before serving, if desired.