Hi.
You're right about Chantecler, more affordable at mid-day, gorgeous room (we last were there before Chef Llorca left, so don't know what will follow his fusion menu) -- if you're staying there it is an easy choice or a great choice if you're hosting guests on an expense account. Your friend was right about Boccaccio, great pan-Med menu, on a pedestrian street above Place Messina.
If you want to keep "high end," L'univers-Christian Plumail, inventive "de Pays" (regional, think pigs feet), at Place Messina, NOT open on weekends. Typical city food, very good, very reliable, Brasserie Flo, above Place Messina, a pre-War theater converted to brasserie, fun.
On the boat basin, L'Ane Rouge, very Niçoise, high end. Or if it's a pretty day and you would prefer to eat on a terrace, Les Pêcheurs a little further down the quai. Both for seafood.
An easy taxi ride outside town in Bealieu-sur-Mer, evening meal only, Réserve de Beaulieu. Nouveau Niçoise, high-style, terrific views (we were last there before Chef Cussac left).