Mix together soy sauce, brown sugar, ginger, garlic, sesame oil and reserved pineapple juice in medium-size bowl. Reserve 1 cup sauce for pasta. Pour remaining sauce into resealable plastic bag; add chicken, pineapple chunks, onion and green pepper. Marinate in refrigerator for 30 minutes, turning once.
Meanwhile, prepare barbecue grill with kiawe (mesquite) charcoal, or heat gas grill or broiler.
Bring large pot of water (do not salt) and oil to boiling. Add pasta; cook until tender, about 3 minutes. Drain; transfer to large serving platter; toss the pasta with the reserved 1 cup sauce.
On metal skewers or presoaked wooden skewers, alternately thread the marinated chicken, pineapple chunks and vegetables.
Grill or broil for 8 to 10 minutes or until chicken is no longer pink in center, turning once. Remove from skewers; arrange over pasta. Sprinkle with macadamia nuts and serve.