Since every chestnut horse has 2 chestnut genes, if you breed 2 chestnut horses - you will always get a chestnut baby. The foal could possibly have white on it or even be an Overo - but its base color will always be chestnut and it will have non black points. Palomino horses carry one chestnut gene and one cream gene. A palomino sire and a field full of palomino mares will not breed true. In this case, you should get about half palominos, with the remainder being chestnut and cremellos.
Cremello horses carry no chestnut genes and two cream genes.
They are considered a double dilute chestnut. Since cremello horses are homozygous dilute, all offspring of a cremello will carry the dilute or cream gene. Breeding it to a bay will produce either a palomino or a buckskin. The bay gene gives a horse black points, black mane, tail and lower legs. Bay genes are dominant over chestnut genes and only one gene has to appear at conception to get a bay foal.