Heat olive oil in a skillet over medium heat.
Add chopped onion and sauté until translucent.
Stir in minced garlic and cook for another minute.
Add ground chicken to the skillet and cook until browned.
Mix in shredded carrots and diced bell pepper.
Pour in soy sauce, hoisin sauce, and sesame oil.
Season with salt and pepper to taste.
Cook for an additional 3-4 minutes until vegetables are tender.
Remove from heat and let cool slightly.
Serve chicken mixture in lettuce leaves, garnished with fresh cilantro.