1Heat oven to 400º F. Pierce squash with fork; place in ungreased square baking dish, 8x8x2 inches. Bake uncovered about 1 hour 30 minutes or until tender.
2Cook and drain spaghetti as directed on package.
3Cut squash lengthwise in half; remove seeds and fibers. Reserve one half for another use. Remove spaghetti-like strands with 2 forks. Toss squash, spaghetti and remaining ingredients. Return spaghetti mixture to squash shell to serve.