Preheat oven to 400F. Lightly grease a large sheet pan and set aside.
Cut each spaghetti squash in half and scoop out seeds. Rub interior of each half with 2 tablespoons vegetable oil and season with salt and pepper. Lay squash halves, cut side-down on prepared sheet pan and bake at 400F 30-35 minutes until squash is tender (you may have to roast longer if using larger spaghetti squash).
Allow squash to cool slightly, then use a fork to shred the inside of squash into noodles. Set aside for a moment.
Heat remaining 1 tablespoon oil in a medium pot or Dutch oven over medium-high heat. Add ground turkey, onion, and pepper and cook until turkey is no longer pink. Add garlic and spices and cook 1-2 additional minutes until fragrant.
Add diced tomatoes, sauce, and beans to pot and bring to a simmer over medium-high heat. Reduce heat to medium and allow to simmer 5-10 minutes, stirring occasionally. Season chili with salt and pepper to taste.
Divide chili mixture between spaghetti squash boats and top with cheese. Broil boats 2-3 minutes until cheese is melted and browned.
Top boats with optional toppings and serve warm. Enjoy!