Roast the spaghetti squash in the oven: Pre-heat oven to 400°F. Cut the spaghetti squash in half lengthwise and scrape out the seeds with a spoon. Lay the two halves skin side up on a baking sheet lined with aluminum foil. Cook in the oven for about 30-40 minutes or until the squash is cooked but still a bit firm. Flip each squash half and let it sit flesh side up until cool enough to handle. Using a fork, scrape the flesh lengthwise to strip it into thin strands. Measure out 4 cups of the strands in a bowl and set aside. (I actually cooked the squash the night before and refrigerated it so the "noodles" were ready to put into the pancit the next evening.)
Heat oil in a wok or large skillet over medium heat. Saute chicken with onion and garlic until chicken is no longer pink.
Stir in cabbage, carrots, green beans and soy sauce. Cook until cabbage begins to soften.
Toss in spaghetti squash "noodles" and cook until heated through, stirring constantly.
Transfer to a serving dish and garnish with cut lemon (we usually squeeze the lemon juice onto our pancit).