Cours Saleya is an incredible place to get some of the Nice atmosphere. It is in the heart of Old Nice, and is chock full of restaurants and it’s the place to see or be seen on weekends. As with many of these "tourist traps" around the world, there are a few things to look out for: No people at rush hour = not so good. Tons of locals = probably good IF you like the local fare. Tons of tourists = probably a combination of good price, at least semi-good food and service.
They have some great seafood here, but please beware! It's not everywhere just because you're close to water. This is mainly, at least according to my taste buds, a snack and drink location. You be the judges of that.
It’s the same as always, let good judgment prevail. I’ll add some good, and some not so good examples in my other restaurant comments.
Bon Appetit!