And yet, the language of courts and such was Italian until 1860, in contrast with Savoy.
If use of judicial language was enough to be a proof of dominant identity, it should mean that Flanders was predominantly French until 1823, then became so again between 1831 and 1898. Of course it doesn't really work like this.
While I would agree it's not incredibly dominant, in my opinion it's a clear inclination.
I think you're confusing historical diglossy and popular inclination : linguistically, Nice was firmly into an occitanophone region, which is widely accepted at this point.
A long history of dominance of Italian trough an upper-middle class is not nearly enough to make it "definitely Italian" or "inclined to be Italian" In the period between the 1860's and the 1880's, the region is generally divided between liberals that mix a pro-Italian and a pro-French republicanist attitude, and a conservative stance that is generally supporting Nice's particularism such as Maulausséna.
Note that most of previous representents of Sarde institutions eventually elected to leave the region, putting an end to any real pro-Italian sentiment, which was more and more used as a convenient way to accuse political opponents.
If you're interested, there's
Le comté de Nice et la France. Histoire politique d'une intégration, 1860-1879 by Henri Courrière, which have the benefit to be supported by sources and not ideologized historiography from any side.
If you're interested on the use of Nissard compared to Italian before the reunion,
there is this interesting article
Very roughly, there wasn't much opposition to whoever ruled Nice, would it be a French or Sarde power during the XIXth as long it doesn't tempers with local particularism and interests, which Sardinians did in significant parts or were percieved as doing so against local language (which was still predominant clerically) and economic interests (such as the free harbour zone). Nice's region tends to be considered at this point as its own thing : would Italy have kept it, it would have turned into some sort of Aosta or SudTirol equivalent.