If you look at the standings, both Barcelona and Real Madrid have the same number of points, namely 60 points. However, Barcelona technically has 63 points. Because, they have not played one more match and we know who will win the match, it must be Barcelona. Because the match will be played in front of their own supporters and the opponent they face is Osasuna which on paper Barcelona is superior to everything.
Pretty true, they have the same points (60 points). Well, we still can't say Barcelona has 63 points because they still don't play against Osasuna. Even if Barcelona is stronger than Osasuna, we don't know the exact result of the match. I think it is not impossible that the match can end up with a draw. Or even it can be a defeat if Barcelona underestimates them. Anyway, playing at home doesn't always guarantee for the win.
In addition, Barcelona's confidence and mentality have increased after defeating Atletico Madrid last week in a very epic manner. So Barcelona's chances are much greater than Real Madrid's to win the La Liga trophy, although there is no guarantee, but statistically Barcelona currently has that chance. So their chances of winning La Liga are big but not in the Champions League.
Barcelona is surely very confident because they always get good results recently. In La Liga, they always win in the last 5 matches. Real Madrid and Atletico Madrid sometimes performed inconsistently, meanwhile Barcelona performed very consistently. Sure, this is a positive sign for Barcelona that they have a bigger chance to win La Liga title.