You will need to cook your chicken and spaghetti squash first. You can cook your chicken in a crock pot, bake it, or-like I did - cook it in the pressure cooker for 10 minutes & then shred it. You could also buy a rotisserie chicken and use that. 

To cook your spaghetti squash: Pre-heat the oven to 400 degrees. Cut your spaghetti squash in half length wise. Scoop out the seeds with a spoon. Spray the insides lightly with olive oil spray and sprinkle with salt and pepper. Place the two halves cut-side down on a baking sheet and poke 4-5 holes in the skin of the squash with a fork. Bake for 30-40 minutes (depending on the size of your squash). 

Pre-heat oven to 350 degrees. 

Spray a large pan with olive oil cooking spray and heat over medium heat. 

Add bell peppers and salt and pepper to taste. Heat for 5 minutes. 

Add in the cooked chicken, diced tomatoes, minced garlic, thyme, basil, and oregano and mix well. Heat for 2-3 minutes. 

Add in the spaghetti squash and spinach, mixing well. Heat for 4-5 minutes. 

Add 1/2 cup of mozzarella and stir. Heat for 1-2 minutes. 

Transfer this spaghetti squash mixture into a 9x13in baking dish. Bake for 10 minutes. 

Remove from the oven and sprinkle the remaining 1/4 cup of mozzarella on top. 

Bake for 8 more minutes. 

Enjoy!