Pre-heat oven to 350 degrees. Drizzle a tablespoon of olive oil over the chicken breast and salt and pepper to season. Place in oven to cook for 30-40 minutes or until cooked. Set aside.
For the Roast Spaghetti Squash
Cut squash crosswise in the center. Using a spoon, clean out the seeds from the center of the squash. Drizzle a ½ of a tablespoon of olive oil inside each of the halves of squash. Lightly salt and pepper each half. Place on cookie sheet with cut side down. Cook for approximately 30-40 minutes at 350 degrees.
Remove from oven and allow to cool slightly. Using a fork scrape the inside of the squash, this will resemble spaghetti noodles. Set aside.
For the Sauce
In a sauce pan heat 2 tablespoons of olive oil over medium heat. Saute onion and cook for 2 minutes or until onion starts to soften. stirring occasionally. Add garlic and cook for one minute. Add wine and allow to cook for an additional minute. Add tomatoes, chicken, mushrooms, roasted red pepper, Italian seasoning, fresh basil, sugar and salt and pepper to taste.
Bring to a low boil, stirring occasionally. Lower temperature to low and cover allowing to cook until mushrooms have softened, stirring every few minutes.
Add the spaghetti squash to the sauce and cook for 3-5 minutes to allow the squash to warm and incorporate with the sauce. Serve and garnish with the chopped basil leaf that you reserved.