Fruit: blueberries, strawberries, raspberries, apples, peaches -- none of these require more than a wash and they don't need to be sliced).
Chips: some of my favorite brands: Que Pasa, Late July, Whole Foods brand blue corn.
Mozzarella/cherry tomato/fresh basil skewers: Yes, Mozzarella should be refrigerated; but, in my experience, if the cheese is covered in original packaging or some kind of container, it should last an hour or so while you drive to your prime viewing destination party!
Nuts: Good for you -- many are high in magnesium; walnuts are known as good sources of essential fatty acids. To ensure that nuts stay fresh as long as possible, refrigerate or freeze; or, store in glass containers. But because they contain both fat and protein, they are excellent as a party adjunct!
Hummus, tahini, or other gluten free dip, veggies: Please note that not all hummus is gluten free! Most is, but I have seen ingredients in some hummus brands that could be problematic . . . tahini, however, is easier as it is comprised of sesame seeds, only, in most cases.
There is always the issue, however, of a food with no gluten ingredients still not labeled as gluten free because the facility itself is not gluten free. I have known people with celiac disease or otherwise high gluten sensitivity who cannot eat anything processed in a facility that is not exclusively gluten free. I, myself, don't think that I have experienced these reactions, but everyone is different.
As an aside, sesame seeds (tahini) are a good source of calcium, according to various sources as well as an article about calcium content of tahini vs. milk from the site I Quit Sugar.