According to the American Kennel Club breed standard for Chihuahuas, any color -- solid, marked or splashed -- is acceptable and correct. Brindle is a coat pattern where there are black or any other darker colored streaks causing pronounced stripes on another color, and it is fairly rare in Chihuahuas.
Chihuahua Coats and Colors
Brindle is a less common color in Chihuahuas because it requires one or both parents to carry the recessive brindle gene. If one parent is solid colored and the other is brindle, chances are the pups will be mostly solid. A brindle dog mated to a sable dog could produce brindle puppies, and a brindle dog mated to a dark dog with tan points could produce black with brindle-pointed pups.