Yes, there is a bus station (gare routiere) in Nice. It's not really a station but more like a collection of islands and curbs where buses commence. It's pretty far away from the center, at Vauban. However, you can pick up the bus 82 or 112 from a stop closer to the center. Like the Boyer stop on Rue Barla -- that one is not obvious, just a sign and no overhead shelter. About a block north of Place Garibaldi.
Now having said that, I've not tried to catch that line during a peak travel season. Some people do go to the end of the line at Vauban to guarantee a seat. You can take Tram Line 1 to Vauban and walk to the stop (through a brief tunnel).
Your most up to date information is via the Lignes d'Azur web site or app. The French language version has up to date information on diversions, schedule changes, etc. (Use translate.google.com if you can not read French).