What can I add to pesto to make it less salty?

The pesto is salty because it has 1.5 cups total of two cheeses, both of which have lots of salt, particularly the Pecorino Romano. AND there's salt added to this. That's too much salt.

Omit the teaspoon of kosher salt from the pesto. If it's still too salty for you, it's time to reduce the two cheeses, maybe cut back to 1/2 cup each but start by cutting out the added salt first.

Don't add ingredients, rather reduce them. Use half as much salt and half as much Parmesan as pesto recipe asks for. Find and use ham made with less salt.

This is a tough one. The only non-salty ingredients are garlic, pine nuts, basil and olive oil. You could add a little more of each to the purée till it tastes ok to you. What kosher salt did you use? I’m guessing that this recipe was originally made with Diamond Crystal kosher salt, which is about half as salty tasting as other brands of kosher salt.