Heat the sesame oil in a skillet over medium-high heat. Add the chicken and cook until the pieces are well-seared and cooked through, 5-6 minutes.
Meanwhile, in a small bowl, combine the chili sauce, soy sauce, garlic, ginger, lemongrass, and sriracha (if using).
Reduce the heat to low and add the sauce to the skillet. Stir to coat, add the scallions and continue to cook until the scallions are wilted and the sauce thickens slightly, about 3 minutes.
To serve, spoon about ¼ cup chicken into each lettuce cup. Top with cilantro, and basil. Serve lime wedges. Enjoy!