Boil the spaghetti squash, whole in a large pot until soft when you push on it. You may need to turn the squash to get it cooked evenly, and if you put a lid on the pot it will speed up the cooking process.
While the spaghetti squash is cooking, brown the chicken in a large skillet with coconut or avocado oil. Before or while it's cooking, chop the chicken into bite size pieces.
Add the mushrooms, onion, and garlic into the chicken and saute all for a few more minutes.
Add the tomato sauce, oregano, basil and simmer for about 10 more minutes at a low heat.
Once the spaghetti squash is cooked through, remove it from the pot of water and let it sit for a few minutes until slicing it in half.
Remove the seeds from the middle of the squash and set them aside. Scrape out the "spaghetti" with a fork.
Put about 1 cup of spaghetti squash on your plate and cover with the chicken marinara sauce.
Enjoy!