Heat your oven to 400 degrees and line a rimmed baking sheet with aluminum foil.
Cut the spaghetti squash in half length wise and scoop out the seeds. Rub the inside with 1/2 Tbsp of the oil and sprinkle with salt. Place, cut-side down on the baking sheet and bake until fork tender, about 45 mins - to one hour. Additionally, spread the pine nuts on a small baking sheet and bake until just golden brown, about 5-10 minutes.
Once the squash is done, heat the other 1/2 Tbsp of oil in a large pan on medium heat. Sprinkle the chicken cubes with salt, garlic powder and onion powder (no measurements, just sprinkle!) and cook until golden brown, about 5 minutes.
Make the pesto
Put the pine nuts into a SMALL food processor (mine is 3 cups) and pulse until crushed. Add in all the remaining ingredients, except the oil, and process until combined, scraping the sides as needed.
With the food processor running, stream in the oil until well combined.
Divide the squash between 2 bowls and mix in 1/2 the pesto with each squash. Top with chicken and additional sliced basil, if desired. Season to taste with salt.