I think the fact that Nice is strong and playing well against PSG this season will be additional factors to motivate PSG players and to play the best of their abilities. The bookmakers estimate PSG's chances of winning at 1.85, which I think is a very favorable odds. An additional factor in favor of PSG is a longer rest than Nice - they continued to play in the French Cup.
PSG are focusing on the UCL match next midweek and on the domestic league they won't have any effect when they fail to get points, I think in this match PSG will play with their back-up players while the main players will be saved against Real Madrid, and so it's huge Nice possibility can take advantage of that and win this match.
I think PSG will play with the main players, They will not take this match lightly and it is important to win this game to make the players mentally ready to face Real Madrid in the middle of this week. and the match proved that PSG was the most powerful in the French League.
putting key players in a game in which they lose doesn't change anything, it would be risky for them to put key players in that game, I doubt the coach will do that, PSG is more focused on the champions league, they know the importance of the champions league and in the championship they already have a guaranteed victory, they don't need to make an effort in this game against nice knowing that in the next game they will play against real madrid in the champions league