Cut the spaghetti squash in half and scoop out the seeds. Place the squash face-down on a sheet pan and set aside. Cut onion, artichoke hearts and garlic as noted.
Next, heat a cast iron skillet (or other oven safe pan) over medium heat. Add in the onions, artichoke hearts and garlic to heat up and soften. Cook, stirring occasionally, for 4-5 minutes until the onions start to soften up.
Scoop the items in the pan aside to make room for the chicken. Season the chicken with salt and pepper and it in the pan to brown on each side - about 5 minutes per side.
Add the tomatoes, kalamata olives and spinach and mix everything together.
Place the chicken skillet in the oven along with the spaghetti squash. Cook for about 30 minutes, depending on the size of your chicken breasts and squash, until the chicken is cooked through and the squash pierces easily with a fork.
Remove the chicken and squash from the oven. Once the squash has cooled for a few minutes, scoop it out with a fork. Serve your Mediterranean chicken and veggies over the spaghetti squash.
Nutrition facts are an estimate provided for those following a Ketogenic or low-carb diet and do not the include spaghetti squash for this recipe. See our full nutrition information disclosure here.