It doesn't matter what Notre Dame's record is in L.A. over the past 40-plus season. The fact of the matter is that if you go back through the most recent games in L.A., any time there is a clear favorite they've won the game in the 2000s. It's not like loaded ND teams have been going to L.A. lately and getting upset by SC teams that played over their head.
You have to go back to '98 for an upset in L.A., but that one has an asterisk because of Jarious Jackson's injury and I'm not sure ND was even favored. The '96 game was the missed PAT game, which was unquestionably an SC over ND upset.
Long story short, Notre Dame is way better than USC and will win. Nothing from the recent history of this rivalry indicates a 5-6 USC team with a frosh QB and lame duck coach is going to beat an ND team that's undefeated and really good on both sides of the ball.