It's very true adding all the uncertainties that comes with football recently its very possible that PSG can act very poorly and other teams take advantage of them to getting to the top of the table that was how it happened few seasons back where PSG later struggled getting to win the league title as they lost it that season.
In a football match anything can happen. But if you look at other teams I think there is very little chance of them beating PSG to win the League. One team that was able to beat them was Lille in the 2020-2021 season and if you look at the statistics it's not like PSG performed badly and then lost points. The competition was very competitive until the end of the season and Lille won the League by only 1 point. This means that to beat PSG you need another team that is also able to perform consistently. NICE has shown good performance some time ago but currently they are inconsistent with winning then losing then winning and then losing again.
Also, if Nice want to really be a contender for the Ligue 1 title, at least Nice should also have a balance of having a high number of goals but only conceding a lower number. Because after all, that factor is also what happened to Lille and Monaco when they managed to get the Ligue 1 trophy competing strongly with PSG at that time . But ya, what is happening now about Nice is the fact that Nice does not have a good number of goals and of course, this factor does not make Nice strong to be able to compete with PSG in the title race. So yes, with results like that, PSG can still guarantee to still win the Ligue 1 trophy this season, because there are no teams that have better quality than PSG this season in Ligue 1.
You are putting the cart before the horse. Where should the Nice players go and ask for a billion in investments for their team? Maybe they should go to church more often and ask the holy football god to turn more of their talents into the next Mbappe, but I don't have any hope this is going to work out.
It is not about what Nice wants, it is about what they are able to do. "If Nice want to..." is what you said. Well, I am sure they want to, but they can't. There is a massive financial imbalance in Ligue 1 and I haven't looked up the numbers, but I guess that the budget of PSG is several times bigger than that of Nice. It is not possible to compete for the title. It can be on very rare occasions, but never for a few years in a row.