Heat one tablespoon of sesame oil over medium heat in a large frying pan. Add the ground chicken and cook for about 5 minutes or until it starts to brown. Peel and finely chop the onion. Add to the pan and mix well. Cook for another 2-3 minutes.
Finely chop the red bell pepper. Finely chop the green chili. Slice the mushrooms. Add the peppers and mushrooms to the pan and stir well. Continue to cook for 12-15 minutes over medium heat. Stir occasionally.
Meanwhile, prepare the sauce. Peel and finely grate the fresh ginger. If your peanut butter is firm, you will need to microwave it for about 30-60 seconds to melt it. In a small bowl, whisk together the soy sauce, hoisin sauce, one tablespoon of sesame oil, rice vinegar, peanut butter, sweetener, garlic powder, and grated fresh ginger.
Pour the mixture into the frying pan with the meat and reduce the heat to low. Stir well. Cook for about 2-3 minutes or until the meat and veggies are well coated with the sauce.
Serve in lettuce leaves. Optionally, sprinkle with some finely chopped peanuts and cilantro. Enjoy!