Carefully slice spaghetti squash in half lengthwise. Scrape out seeds with a spoon. Drizzle both halves with 1 tablespoon of the olive oil, then season with salt, pepper, and garlic powder.
Place squash cut side down on a baking sheet and roast for 30-40 minutes, or until insides easily pull away with a fork. Baking time will depend on size of spaghetti squash. Remove from oven and allow to cool slightly.
Using a fork, pull spaghetti squash flesh into loose "noodles", being careful to keep the outer skin intact (this will be your bowl).
Meanwhile, in a saute pan over medium heat, add 1 tablespoon of olive oil. Crumble chorizo into pan. Add diced bell pepper and onions. Saute until meat and is browned and cooked through, and vegetables are tender.
Spoon half of chorizo mixture onto each spaghetti squash bowl. Sprinkle with mozzarella cheese and enjoy.
Optionally, place spaghetti squash under your oven broiler for 2-3 minutes or until cheese has melted and browned slightly.
If you're having trouble slicing your spaghetti squash in half: Slice the very top and bottom of your spaghetti squash off, giving you a flat surface for slicing your squash in half lengthwise. If you're still having trouble, pierce your squash all over with a fork and microwave for 2-3 minutes, or until skin has softened enough to slice through.