I would really consider dropping the processed foods from your menus. Summer is a great time to eat both seasonally and locally. Things I plan on doing/keeping in the fridge this summer:
Keeping a big bowl of already prepped veggies in the fridge - sliced up bell peppers, carrot sticks, broccoli & cauliflower, grape or cherry tomatoes, kohlrabi, mild radishes. These are great to munch on or dip.
Greek yogurt - add chopped cucumber and mint OR add tahini and a little cumin OR add chopped fresh fruit - instant dip and/or smoothie.
Bulghur/quinoa and other 'salad' grains. Really versatile - add chopped tomatoes, cucumbers, peppers (really whatever you have), mint, lemon and a bit of olive oil and a really fast cold main dish or salad. You can vary the seasonings (lemon, oregano and garlic go more Italian, lime & cilantro for a touch of Thai). Add some chopped peanuts, cashews or slivered almonds for a bit more protein.
Hard boiled eggs. I LOVE them. Make egg salad, or just chop them over a salad.
Salad is a great idea. I find it lasts better if you prep the greens, wrap in a kitchen towel and refrigerate separately from the other veggies. Since your nanny can cook, I am sure she can just combine the greens with the other veggies and dress (or not).
Grilled cheese with fresh tomatoes. Put the tomato on the toasted bread, the cheese goes over it, then broil. I am not sure this counts as a cooked meal or not.
Cold soups. Gazpacho, chilled tomato and basil, yogurt and cucumber.
I am not sure about the comments about real foods being 'unrealistic'. None of these items takes more than 10-15 minutes to prepare and all are make ahead (except the grilled cheese which seriously my 6 year old can make) - often several days ahead. @Kay - my son has actually never been to McDonalds (or any other fast food place) and I just ate at Emeril's last week - it was WONDERFUL - but not really in the healthy food category :)