Season chicken with garlic powder, paprika, salt, and pepper. Whisk together 1 1/2 cups water with soy sauce and vinegar in a 2 cup measuring cup or bowl. Set aside.

Heat 1 tablespoon oil in a large deep skillet over medium-high heat. Add chicken and cook, stirring occasionally, until browned on all sides (Chicken will not be cooked through at this point). Remove chicken from skillet and set aside.

Add remaining neutral oil and sesame oil to skillet. Add garlic and ginger and cook until fragrant, about 1 minute, stirring constantly. Stir in crushed red pepper. Add pasta and stir to coat in garlic mixture. Add reserved soy sauce mixture and stir until everything is well incorporated, scraping any browned bits from bottom of skillet. Bring mixture to a boil and reduce to simmer.

Add chicken and any accumulated juices into skillet along with brown sugar. Stir and cook, stirring occasionally, until pasta is cooked and sauce is thickened, 10 to 12 minutes. Add additional water as needed to keep mixture saucy until pasta is cooked. Stir in green onions, sesame seeds and more crushed red pepper if desired.