Preheat the oven to 425 degrees F.
Spread the squash out in a single layer on one or two baking sheets. Drizzle with olive oil, nutmeg, salt, and pepper; toss well to coat. Roast until the squash are tender, about 20 minutes. To the pan(s), add the broccoli rabe and sage leaves. Drizzle with a 1 tablespoon olive and a pinch of salt + pepper. Toss well to combine with the squash. Place back in the oven and roast for 10 more minutes or until the broccoli rabe is tender crisp and the sage leaves are crispy. Remove from the oven.
Meanwhile bring a large pot of salted water to a boil. Boil the pasta until al dente. Before you drain the pasta scoop out about ½ cup pasta water, drain the pasta well.
While the pasta is boiling, place a large skillet over medium heat. Add a drizzle of olive oil and once hot add the pancetta. Let the pancetta get nice and crispy, about 2-3 minutes. Now toss in the minced garlic and sauté for about 1 minute to soften. Add the drained pasta to the skillet and give it a good toss, cook for about 2 minutes.
Beat together the eggs and Parmigiano-Reggiano in a glass measuring cup. Remove the pasta from the heat and pour the egg/cheese mixture into the pasta, tossing quickly (to ensure the eggs do not scramble) until the eggs thicken and create a sauce. Thin the sauce with a bit of the reserved pasta water, until it reaches your desired consistency. Add the squash, broccoli rabe, and sage and gently toss to combine with the pasta.
Season the carbonara with plenty of freshly ground black pepper and salt to taste.
Divide the pasta among plates and top with freshly grated Parmigiano-Reggiano cheese and parsley. Grab a fork and start twirling!