Bring a large pot of salted water to a boil. Cook the spaghetti according to the package instructions. Drain, then drizzle with 2 tablespoons canola oil and toss. Set aside.
Meanwhile, whisk together the mirin and 2 tablespoons of the soy sauce in a large bowl. Add the chicken pieces and toss to coat.
In a separate bowl, whisk together the chicken broth, chili sauce, sambal, vinegar, sesame oil, 2 teaspoons of the cornstarch and remaining 2 tablespoons soy sauce.
Fill a large, heavy-bottomed skillet halfway with canola oil and heat over medium-high heat until shimmering but not smoking. Toss the chicken with the remaining 1/2 cup cornstarch until coated completely. Add the chicken to the hot oil in batches and cook until golden brown and cooked through, about 1 minute per side. Remove with a slotted spoon to a plate; cook the remaining chicken.
Pour off all but 2 tablespoons of the oil and return the skillet to medium-high heat. Add the peanuts and cook until toasted to a dark brown, about 1 minute. Add the scallions, chiles and garlic and cook, stirring constantly, until lightly toasted, about 1 minute. Add the chicken broth mixture to the skillet and bring to a boil. Return the chicken to the skillet with the pasta and heat, tossing, until the pasta and chicken are fully coated and hot. Serve warm.
Copyright 2017 Television Food Network, G.P. All rights reserved.