How to Make It
Prepare noodles according to package directions; set aside.
Heat 2 tablespoons oil in a large skillet over medium-high. Add bell pepper and onion and cook, stirring often, until they begin to soften, about 4 minutes. Add snow peas and cook, stirring often, until vegetables are tender, 2 to 3 minutes. Remove from skillet; set aside.
Add remaining 1 tablespoon oil to skillet; add chicken in a single layer. Cook, turning once, until browned and cooked through, about 8 minutes.
Meanwhile, whisk cornstarch and ¼ cup water in a small bowl. Stir in marmalade, vinegar, tamari, salt, and black pepper.
Add cornstarch mixture to chicken; bring to a boil over medium-high. Cook, undisturbed, until sauce thickens and chicken is glazed, about 1 minute. Return vegetables to skillet and toss to coat.
Serve chicken and vegetables over noodles, topped with peanuts and scallions.