To make Peanut Sauce: In small saucepan over low heat, combine peanut butter, soy sauce, rice vinegar, brown sugar, garlic sauce, lime juice, garlic, ginger, fish sauce, milk and water. Add more water for thinner sauce, if desired.
To make Lettuce Wraps: Fill lettuce leaves with chicken and Peanut Sauce; top with bell pepper, onion, carrots, cucumber, basil and mint. Sprinkle crushed peanuts on top and garnish with lime slices.