Preheat and prep the squash: Heat the oven to 400°F (205°C). Carefully slice the spaghetti squash in half lengthwise and scoop out the seeds. Brush the cut sides with oil and sprinkle with salt and pepper.

Roast until tender: Place squash halves cut side down on a baking sheet lined with parchment. Roast 35–45 minutes, until the flesh strands easily with a fork but isn’t mushy.

Shred the chicken: While the squash roasts, pull your cooked chicken into thin shreds. If using rotisserie, remove skin and bones first. Season lightly with salt and pepper.

Make the buffalo mix: In a skillet over low heat, warm the buffalo sauce and butter (if using). Stir in garlic for 30 seconds. Remove from heat and whisk in Greek yogurt or blended cottage cheese until smooth and creamy.

Combine with chicken: Add the shredded chicken to the sauce, tossing to coat. Stir in diced celery if you like extra crunch.

Shred the squash: When the squash is done, flip it cut side up and let it cool for a few minutes. Use a fork to gently pull the flesh into spaghetti-like strands, keeping the strands inside the shells.

Mix and fill: Add half of the mozzarella to the chicken mixture. Fold the sauce and chicken into the squash strands right inside each shell until combined and evenly distributed.

Top with cheese: Sprinkle the remaining mozzarella and the blue cheese or cheddar over the tops.

Back to the oven: Return the filled boats to the oven for 8–10 minutes, until the cheese is melted and bubbling at the edges. For extra color, broil 1–2 minutes—watch closely.

Finish and serve: Let rest 5 minutes. Drizzle with ranch or blue cheese dressing if desired, sprinkle with green onions, and add a few grinds of black pepper. Serve hot.