Hmm, if DS were going to nursery 5 days a week and would have 3 meals/day there, plus snacks in between, I'd like the following:
one hot/cooked meal per day, the other meals/snacks can be cold
some sort of fruit or veg as part of every meal
some sort of carbohydrates as part of every meal (bread, potatoes, pasta, rice, ...)
some source of calcium at least once per day
protein rich stuff (meat, eggs etc.) every other day or so
fish twice per week
on the whole, should be low in salt and sugar, and a meal is complete without a dessert - a dessert is allowed occasionally but NOT as an everyday, essential part of meals. Food should only occasionally be deep fried, and should be prepared in such a manner as to preserve the nutrients.
for snacks: fruit, dried fruit, fruit bars, raw vegetable sticks, cheese, yoghurt/fromage frais, low-sugar cookies/biscuits, slice of bread/toast, occasionally (once a week or so) chocolatey stuff. Snacks such as crisps are allowed once per month or so.
for drinks: Water. I'm happy to drink nearly nothing except water and tea, I don't see why my child should need anything else. Also, it's cheap!