If my opponent's Active Pokemon has the "Omega Barrier" Ancient Trait, can I use Lysandre to switch one of my benched Pokemon with it?

If your opponent's Benched Pokemon has "Omega Barrier", then Lysandre's effect will be blocked. But choosing a Benched Pokemon without "Omega Barrier" will cause it to switch with the Active Pokemon because the Benched Pokemon is the target of Lysandre.

Relevant cards

XYP_XY49