2 Tbsp. soy sauce
1 Tbsp. dark brown sugar
1 tsp. fish sauce
1 Tbsp. sambal oelek or Sriracha, plus more for serving
2 Tbsp. vegetable oil
3 scallions, white and pale green parts only, thinly sliced
2 garlic cloves, finely chopped
1 lb. ground chicken
Kosher salt
Bibb lettuce leaves, lime wedges, and tender herbs (for serving)