Wash the sweet potatoes thoroughly under cool running water and scrub away any dirt from the skin. Pat them dry with paper towels and pierce each potato 5–6 times using a fork to allow steam to escape during cooking.
To bake the sweet potatoes, preheat your oven to 400°F (200°C). Place the potatoes on a baking sheet and bake for 45–55 minutes, or until they are fork-tender. Alternatively, microwave each sweet potato for 5–8 minutes, turning halfway through cooking, until soft.
While the sweet potatoes are cooking, place the shredded cooked chicken breast into a medium mixing bowl. Add the buffalo sauce and stir thoroughly until all of the chicken is evenly coated with the sauce.
If the chicken mixture has cooled, transfer it to a microwave-safe bowl and heat for 30–60 seconds until warmed through. Stir again to redistribute the buffalo sauce evenly.
Once the sweet potatoes are fully cooked, carefully remove them from the oven or microwave and allow them to cool for 2–3 minutes until they are safe to handle.
Using a sharp knife, slice each sweet potato lengthwise down the center without cutting completely through the bottom. Gently press the ends inward and fluff the interior flesh with a fork to create space for the filling.
Divide the buffalo chicken mixture evenly between the two sweet potatoes, spooning it generously into the center of each potato.
Drizzle 1 tablespoon of light ranch dressing over each stuffed sweet potato and sprinkle with chopped green onions for freshness and flavor.
Serve immediately while warm. For meal prep, store the sweet potatoes and buffalo chicken separately and add the ranch dressing and green onions just before serving.