Roast the squash: Preheat oven to 400°F (200°C). Halve the spaghetti squash lengthwise and scoop out the seeds. Drizzle cut sides with 1 tablespoon oil, season with salt and pepper, and place cut-side down on a baking sheet. Roast 35–45 minutes, until the flesh is tender and shreds easily with a fork.

Crisp the bacon: While the squash roasts, cook chopped bacon in a large skillet over medium heat until crispy. Transfer bacon to a plate lined with paper towels. Leave 1–2 tablespoons bacon fat in the pan for flavor.

Cook the chicken: Season chicken with salt and pepper. Add remaining 1 tablespoon oil to the skillet if needed. Sauté chicken over medium-high heat until browned and cooked through, 5–7 minutes. Transfer to a plate and tent with foil.

Make the Alfredo base: Reduce heat to medium. Add butter to the skillet. When melted, add garlic and cook 30–60 seconds until fragrant (don’t brown it).

Add cream and broth: Pour in heavy cream and chicken broth. Stir and bring to a gentle simmer. Let it bubble 3–5 minutes to thicken slightly.

Finish the sauce: Whisk in Parmesan a handful at a time until smooth and creamy. Add nutmeg and red pepper flakes if using. Taste and season with salt and pepper. If it’s too thick, splash in a little more broth or cream.

Shred the squash: When the squash is cool enough to handle, use a fork to pull the strands into a bowl. Pat with paper towels if very watery.

Combine everything: Add the squash strands to the sauce. Toss gently to coat. Fold in the cooked chicken and half the bacon. Warm through for 1–2 minutes so it all mingles.

Garnish and serve: Top with remaining bacon, extra Parmesan, and chopped parsley. Serve hot. For a fun presentation, pile it back into the squash shells.