Place springform in large roasting pan; pour hot water into roasting pan until one-fourth full. Bake uncovered 40 to 45 minutes or until center is almost set. Remove cheesecake from roasting pan. Run knife around edge of cheesecake to loosen. Cool completely at room temperature, about 2 hours. Cover and refrigerate at least 2 hours but no longer than 48 hours. Remove side of pan. Garnish with toasted walnuts. Cut into wedges. Serve with crackers.