Cook the Noodles: Bring a pot of salted water to a boil, add egg noodles and cook until al dente, about 5-7 minutes. Drain and set aside.

Sear the Chicken: Heat vegetable oil in a skillet over medium-high heat, season chicken with salt and pepper, and cook until golden brown and cooked through, about 5-7 minutes. Remove and let rest.

Sauté the Garlic: In the same skillet, add more oil, reduce heat, and sauté minced garlic for about 30 seconds until fragrant.

Stir-Fry the Vegetables: Add red bell pepper and broccoli, stir-fry for 3-4 minutes until tender-crisp.

Return the Chicken: Add chicken back to the skillet, mix with garlic and veggies.

Add the Sauces: Whisk soy sauce, oyster sauce, brown sugar, and chili flakes in a bowl, pour over chicken and vegetables, stirring for 1-2 minutes.

Combine with Noodles: Add drained noodles, toss everything together for about 2 minutes until well-coated.

Garnish and Serve: Transfer noodles to bowls, garnish with green onions and sesame seeds, and serve.