To a large skillet, such as a saute pan with high sides, cook bacon. Heat pan over medium-low heat and add the bacon. Cook until the fat is rendered and the bacon is crispy. Once crispy, remove it with a slotted spoon and place it on a paper towel-lined plate to drain any excess grease.
Remove approx 2 tablespoons of the bacon grease from the skillet and reserve it for the sage. Add the butternut squash cubes to the skillet with a sprinkle of salt and pepper, and nutmeg. Cook, stirring occasionally, until the squash is just fork tender, do not overcook, about 4-6 minutes.
Using the same saute pan, heat over medium-low heat and add ½ the reserved bacon grease. Add the arborio rice and stir. Toast the rice until the pieces are translucent and just fragrant. Stir in the garlic and cook for another minute. Stir in the white wine, constantly stirring or at least stirring every minute or so, until the rice absorbs the wine. Once the wine is absorbed, add in 1½ cups of the chicken stock, stirring until the rice absorbs the liquid like it did with the wine. Repeat this 2 to 3 more times, until all stock has been added and the rice is al dente, just firm. You want it to appear a little wet – and want there to be some liquid left when serving. We don't want a dry. The entire stirring process will take about 15 to 20 minutes.
Once the rice is cooked, stir in the butternut squash cubes, grated Parmesan cheese and almost all over the bacon, leaving some for the topping. If desired, take remaining reserved bacon grease, and heat over medium heat. Toss in fresh sage leaves, and allow to crisp, this will only take about 1 minute.