The Thai dipping sauce that is sweet, thick, and commonly served with fried chicken is nam chim kai. Its name literally means “chicken dipping sauce”: nam chim means dipping sauce, while kai means chicken.
Nam chim kai is a bright, sweet-and-spicy sauce usually made with red chilies, sugar, vinegar, garlic, and salt. It has a thick, syrup-like consistency and is commonly served with grilled or fried chicken, though it also works with spring rolls, fried fish cakes, seafood, and other snacks.
A common mix-up is Sriracha. Both sauces contain red chilies, but Sriracha is generally a smoother hot sauce with a stronger garlic-and-vinegar profile, while nam chim kai is notably sweeter and thicker. Nam pla means fish sauce, and nam prik pao is a roasted chili paste, so neither matches this dipping sauce.
Nam chim is a broad Thai category rather than one single recipe. Other varieties include nam chim chaeo, often served with grilled meat, and nam chim thot man, a version served with Thai fish cakes and commonly combined with cucumber, peanuts, and coriander.