Bring a large pot of water to a boil to cook the pasta. While it comes to temperature, place the oil in a large skillet set over medium heat. When hot, add the garlic and cook until fragrant, about 30 seconds. Add the wine, oregano and chili flakes. Bring to a simmer, and cook until the wine is reduced by half. Add the pumpkin and stock and whisk to combine. Bring to a simmer, cook 2 minutes, and then remove from the heat.
When the water is boiling, lightly salt it, and then add the pasta and cook until tender, about 8 minutes. When the pasta is almost cooked, set the skillet with the pumpkin sauce back over medium heat and return to a simmer. Whisk in the cream and nutmeg; season with salt and pepper.
When the pasta is cooked, drain it well, reserving ½ cup of its cooking liquid. Add the pasta, reserved cooking liquid and ¼ cup Parmesan cheese to the skillet and toss to combine. Divide the pasta among bowls and top with nuggets of Gorgonzola cheese, walnuts and parsley. Serve with additional Parmesan cheese for sprinkling on the pasta tableside.
Note: To toast the walnuts, place them in a skillet and set over medium heat. Cook and stir until lightly toasted and aromatic, about 4 to 5 minutes.