In a large microwave-safe bowl, combine vegetable stock, soy sauce, sesame oil, garlic powder, red pepper flakes, and sweet chili sauce. Microwave for 2 minutes.
Whisk in the peanut butter and the whites of the scallions until smooth.
Add the ramen noodles to the bowl, coat them in the broth by turning them over several times. Microwave for 1 minute, then flip the ramen and microwave for another minute.
Stir well until the noodles are separated and coated in the broth. If the noodles are slightly firm, microwave for an additional 30 seconds.
Let the noodles sit in the broth for a few minutes to thicken into a sauce.
Serve warm, garnished with the green parts of the scallions and sesame seeds.
Notes
For added flavor, consider topping with sliced boiled egg, shredded chicken, or tofu.