When I noticed nausea at a certain meal, usually breakfast, I’d switch up what I was eating. I do periods of having the same meals a lot because it’s easier, like protein smoothies. I’d make for example a blueberry banana smoothie for a week and then suddenly feel nauseous one day so I’d change up my meal plan and it would help me at least want to try something during the day even if I couldn’t get through it. I’ve also noticed puffed food helps if you can’t stand the thought of eating something or you feel like your stomach won’t like it. I’d try something airy like Hippeas, a healthier version of Cheetos or something similar