There are some parts of the world, Africa and Asia among them, where it would be almost criminal not to taste fragrant and flavorful street food. However, I can (or at least I can try to)understand that some people worry about the sanitary consequences of such acts. I remember a trip to Morocco where I spent most of my time between my bed and the bathroom. But I also keep a vivid memory of the fantastic meal that caused this small (in retrospect...) inconvenience : unforgettable ground beef skewers with a tomato salad. In short, I think that nothing should ever prevent us from being adventurous eaters (and I can hear Tony Bourdain concurring loudly in the background!).
No such concerns though in Nice where you can indulge on local street food as safely as possible. And this culinary journey should start at Rene Socca. You will have to wait in line before the outdoor counter, sometimes for long minutes, to be served your choice of socca (typical Nicois dish that is essentially a thin chickpea flour pancake), pissaladiere (onion tart with anchovies and olives), petits farcis (stuffed vegetables) or pizza. But your patience will be rewarded as the socca, that is taken out directly from the oven and cut from large oval baking sheets, is out of this world and the pissaladiere no less delicious. Avoid the farcis though (bland and reheated in a microwave oven). And don't pay attention to the uncaring service either (waiters were playing street soccer that day while serving us).
Then tour the beautiful winding streets of Vieux Nice and, once you think you have walked enough to deserve a sweet treat, make a stop at Fenocchio where you are sure to find some of the best ice-creams and sorbets in the world. Feel free to try the most extravagant flavors such as swiss chard pie, chewing gum or Mascarpone. I'm personally fonder of their more classic creations like pear, passion fruit or lemon. In any event, only few things can rival the pleasure of eating an ice-cream with the ones you love at an outdoor table on Place Rossetti.
If your stomach can still accommodate more food, I recommend that you buy a bag of local biscuits (navettes, mantecaos, mendiants, ...) in a good bakery or at Lou Canice, a provencal specialty food store located not far from Fenocchio. I'm sure you will enjoy as much as I do the wide variety of textures (from tough-to-bite to crumbling-in-your mouth) and flavors (lavender, anise, orange flower, chocolate, ...) they offer. And after that, I dare you to tell me that Nice is not one of the most wonderful cities in the world.
Chez Rene Socca
1 rue Pairoliere
2 place Rossetti
7 bis rue Mascoinat