Cook the wide rice noodles according to the package directions. Drain well and set aside.
In a small bowl, whisk together 1/3 cup tamari or soy sauce, sweet Thai chili sauce, toasted sesame oil, rice vinegar, chopped ginger, chili flakes, and 1/4 cup water. Set the sauce aside.
Place the sliced chicken in a large skillet and toss with the flour or cornstarch until lightly coated.
Add 2 tablespoons of butter and place the skillet over medium to medium-high heat. Cook the chicken for about 5 minutes, turning as needed, until golden, crispy, and cooked through to 165°F (74°C).
Add the remaining tablespoon of butter, 1 tablespoon tamari or soy sauce, and chopped garlic. Cook for about 1 minute, stirring frequently, until the garlic is fragrant. Transfer the chicken to a plate.
Add the shallot, bell peppers, and scallions to the same skillet. Cook for about 5 minutes, stirring occasionally, until the vegetables are crisp-tender.
Pour the prepared sauce into the skillet. Add the cooked noodles and crispy chicken.
Toss the 20 Minute Crispy Garlic Chicken Noodles until everything is evenly coated. Cook for another 3–5 minutes, or until the sauce has thickened slightly and clings to the noodles.
Stir in half of the chopped basil and remove the skillet from the heat.
Serve immediately with the remaining fresh basil and a sprinkle of sesame seeds.