Travel to Nice

We looked into doing this in 2021. I believe the train was about 5-6 hours and flights took about 3-4 hours. Both methods were similar in cost.

Looking at "Google Flights", I don't see any non-stop flights but Vueling, Iberia, Air France, and others all have connecting flights between the two cities.

Looking at the Italian train website, Trenitalia, I see trains from Milan to Ventimiglia, then change trains to go to Nice in 5 hours at a great price!

https://www.trenitalia.com/en.html

It takes about 5 hours by train, with a change at Ventimiglia. There aren't a lot of departures offering that travel time. The best I can tell from checking quickly, this will require an ItaIian train and a French train. I don't believe you can buy the whole deal through either Trenitalia or SNCF Connect, though SNCF does display the total fare. If you want to make a single purchase, one option is thetrainline.com, which usually charges a bit more than the train companies.

At 5 hours, the train would be considerably faster than flying, city center to city center if there are no non-stop flights.

There are no non-stop flights, making the train the most reasonable way to go! Buses take longer and are less reliable.

We took the 'high speed' train, which was supposed to get us from Paris to France in under 6 hours... had a mechanical breakdown and it took 11 hours. Ugh. Still navigating paperwork for a refund.

I also prefer renting a car and making a road trip out of it. You can stop by in Annecy Chamonix or other cool spots in France on your way to Nice.

But going by car is only affordable if you're driving your own car or are making a round trip. The international drop charge on a one-way rental would almost certainly be most unpleasant.