It's almost impossible for Nice to participate in European cups. They played successful matches in the league in the last weeks, but they could not show enough performance. It would be a miracle if they won against PSG. It was expected and they lost 2-0. Now they can't save any more points because Psg wants the championship.
Instead of expecting Nice qualify for the League, then I think one from Monaco and Marseille and Lens are the most likely teams to be there next season. Monaco, Marseille and Lens do not have much difference in points, so one of the three is expected to qualify for the Champions League and Europa League next season. About PSG, they are the favorites for the title, it's very possible.
PSG are 6 points ahead of Lens after winning against Nice a few days ago. His position is safe from Lens, but Lens has the opportunity to close the gap if he manages to win full points next week from PSG, which in my opinion is difficult. I think PSG will eventually widen the safety gap from Lens to 9 points, I hope it is.