Season chicken pieces well in patis and ground black pepper. Set aside.
In a pan over medium heat, sauté garlic, onion, ginger, and lemongrass until fragrant.
Add chicken and sauté just until the chicken turns opaque.
Add chicken stock, and coconut milk. Lower heat and simmer until chicken is cooked through, about 20 – 25 minutes.
Add papaya and boil until tender. Add chili leaves and adjust taste as needed with patis and pepper.