Prepare noodles according to package directions; set aside.
If frozen, rinse ice glaze from halibut under cold water; pat dry with paper towel. Heat large, nonstick skillet or wok over medium-high heat. Brush both sides of halibut with half of the sesame oil.
In heated skillet, cook fish, uncovered, about 3-4 minutes, until browned.
Shake pan occasionally to keep fish from sticking. Turn halibut over; reduce heat to medium and cover. Cook 5-7 minutes for frozen halibut or 2-3 minutes for fresh/thawed fish, cooking until fish is opaque throughout. Transfer fillets to plate; cover to keep warm.
Wipe out skillet/wok with paper towel. Add remaining sesame oil. Heat to medium-high then add and stir-fry bok choy, snap peas, mushrooms and green onions. Stir in noodles; turn off heat. Cover and keep warm.
In saucepan, blend miso, water and teriyaki sauce. Bring mixture to boil then reduce heat to a simmer and cook 1 minute. Stir sauce into warm noodle-vegetable mixture. To serve, divide and portion mixture into 4 bowls or plates. Top each with halibut fillet.
Nutrition information per serving: 571 calories; 15 g total fat; 2 g saturated fat; 22% calories from fat; 56 mg cholesterol; 38 g protein; 71 g carbohydrate; 7 g fiber; 1,643 mg sodium; 77 mg calcium; 219 IU vitamin D; 350 mg omega-3 fatty acids.