If you struggle with nausea through this then you have to just eat what you can. If that’s bland food then so be it. I think the first real important thing to get enough of would be fibre to stop constipation.
If you have a blender, fruit smoothies are so easy to make and really easy to drink if you cant eat much. I have a ninja nutribullet that makes things very easy. I could put 1 small bananas, 1 kiwi (skin left on) frozen blueberries and mango. The prefect high fibre smoothie. You can add chai/ground flax seeds for more. Honey for some sweetness.
Also a handful of walnuts/almonds each day are great for fibre and protein. I eat these everyday sometimes with some dried cranberries or pitted dates/prunes.
The next thing after fibre to get enough of would be protein. Lean meats like chicken, turkey. Salmon (I had tinned salmon today with loads of vinegar, very old school) and lots and lots of anything green and colourful. Brocoli, green beans, cucumber, peppers, carrots. If you dont like eating vegetables cooked just wash them and chomp on them raw. You can dip them in a garlic dip or hummus. Anyway you can eat it then do that. You could even blend food up into soups if that makes it easier to eat.
I drink a protein shake called Huel black edition. They are pricey but they are easy to drink and full of protein.
I’m a real foodie at the moment haha. I’m determined to get through this with good food and lots of walking 
time will tell how well it goes