I have chronic nausea that makes it impossible to keep food or liquid down, multiple days a week what can i do to keep from getting malnourished?

Treat nausea/vomit: Sounds like you have vomiting as well. Obviously you need to treat the nausea. See a GI specialist &/or integrative MD for a through evaluation. You may have parasites or other chronic infections, heavy metal toxicity or other toxins, poor intestinal motility etc. Are there emotional factors? Many drugs & herbs may help, from Zoran to cannabis, ginger & triphala. Consider acupuncture & homeopathy.