Ohhhh I sooooo understand you, I have never had a dog who had to go though chemo. I have friends who have had dogs who did and they were all dealing fine with it.
Dogs will most likely not experience nausea or infections, they can but very very few do so. I read a figure that only 7% of all the dogs going through chemo has to be hospitalized because of the side effects.
Quite a few of them will loose their whiskers, but hardly none loose the hair on the body. There are four breeds that I know of that have a rather high risk of loosing hair during chemo, Old English Sheepdog, Poodle, Shih Tzu and Lhasa Apso. Most other breed have no such problems.
So all in all I think dogs deal with chemo way better than most people do. Im afraid I can not help you with the diet, I am sure you have spoke to the vet, some things I would probably do is to add enzymes to the food also antioxidants and keep up the regular omega 3 and MSM and maybe Biotin aswell, most of these supplements are things I always give my dogs, but in a situation where they will go through the stress chemo after all is, I would probably add it, even if you usually dont give it, but please talk to your vet before. I found a link for you with natural supplements and products to give dogs during cancer treatment.
http://www.allergicpet.com/products/cancer.html?source=GoogleCancerAdWordGive Daisy a big ol' hug and lots of slobbers from me and all my fur kids and please keep us updated. I will keep her and all of you in my prayers and send good vibes your way.
Marit