I tried almost all the options everyone has mentioned and my oncologist agreed that a regime that we follow when morning sickness type nausea kicks in is the one that most people seem to follow. For me, just finding moist, light foods, ginger beer and Jatz crackers did the job most of the time. One of the nurses suggested a boiled egg to nibble on and a glass of lite milk every morning was a good start and a little bit of what I felt like for the rest of the day was good enough and provided enough nutrition.
Good luck with the Port-a-cath. Mine is my best friend!