Whisk the sauce. In a small bowl, combine soy sauce, hoisin, oyster sauce, honey, rice vinegar, sesame oil, and sriracha. Taste and adjust sweetness or heat.
If you like a thicker glaze, stir in the cornstarch slurry and set aside.
Prep the veggies. Dice the onion and bell pepper, mince the garlic and ginger, chop the mushrooms, and slice the green onions. Drain and dice the water chestnuts.
Brown the chicken. Heat the oil in a large skillet over medium-high heat. Add the ground chicken and break it up with a spatula.
Cook until no longer pink and lightly browned, 5–6 minutes. Season with a pinch of salt and pepper.
Sauté aromatics. Push the chicken to the sides of the pan. Add onion, bell pepper, mushrooms, garlic, and ginger to the center.
Cook 3–4 minutes, stirring, until softened and fragrant.
Add sauce and simmer. Pour the sauce over the mixture and stir well. Let it bubble for 1–2 minutes, until slightly thickened and glossy. Fold in water chestnuts and most of the green onions.
Cook 1 more minute to warm through.
Assemble the wraps. Spoon the hot filling into lettuce leaves. Top with remaining green onions, nuts, herbs, and a squeeze of lime if you like.
Serve immediately. Enjoy as is, or pair with steamed rice, cauliflower rice, or a quick cucumber salad.