If you just eat egg fried rice using ingredients from Aldi you’re able to bring your weekly food costs down to about £2-£3 a week, I lived that way for about 3 months during the cost of living crisis. Sure it was only 1000 calories a day but I was able to get all the nutrients I needed from the ingredients.
And if you're truly worried about making sure that you have minimal nutrition to survive on, that is literally the thing that multivitamins were invented to address.
Sure, you won't be living your absolute maximum healthiest lifestyle by doing this but if you've got to get through a couple of tight months this is the way to do it. The Dollar tree sells multivitamins. $1.25 for a month supply is not hopefully going to break the bank.
I think eggs have pretty much all the nutrients you need. They are high in cholesterol though. Same thing with milk. They are the sole nutrition for animals for a period of time, so they have everything needed in it (at least everything the animal needs).