Separate Swiss chard into ribs and leaves; cut into 1-inch pieces. In large pot of boiling salted water, cook Swiss chard ribs for 7 minutes. Add leaves and cook for 3 minutes. Drain and rinse under cold water; drain and set aside. In large skillet, heat oil over medium heat; cook onion, garlic, salt, papper and hot pepper flakes for 5 minutes or until softened. Add Swiss chard, raisins and vinegar; toss together. Keep warm over low heat. Meanwhile, in large pot of boiling salted water, cook penne for 8 to 10 minutes or until tender but firm; drain and toss with Swiss chard mixture. Serve garnished with pine nuts.