Swiss and easyJet fly from Nice to Geneva 3 times a day. Alternatively, French Railways (SNCF) operates a train from Nice to Geneva once daily. Tickets cost $110 - $170 and the journey takes 6 h 21 min.
From Nice Ville train to Nice airport, fly to Geneva airport, then train to Geneva. 2 h 20 min $70. From Nice Ville train to Geneve. 6 h 21 min $146. From Nice bus to Turin, Torino then bus to Geneva. 9 h 25 min $99. From Nice drive to Geneva. 5 h 41 min $89.