Step 1Heat the sesame oil over medium-high heat. Add the lean ground chicken and cook for 5-7 minutes until cooked through. Break it up as it cooks with a wooden spoon and cook until no longer pink.
Step 3In a small bowl, mix together the hoisin sauce, soy sauce, rice vinegar, sesame oil, and chili paste. Taste and adjust the spice level if desired.
Step 4Add the chicken to the slow cooker. Stir in the mushrooms, red bell pepper, and carrots. Pour sauce on top and stir everything together. Cook on low for 3-4 hours.
Step 5When ready to eat, mix in the water chestnuts. Serve in lettuce wraps. Top with cilantro, green onions, and crushed peanuts if desired. If needed, add a cornstarch slurry to the slow cooker to thicken the sauce.