yes, you can!
you should search for Difficulty: Normal or replace the "normal" with any difficulty you want. (this applies to web Steam Workshop system, not in-game one, because the update is not out yet atm)

I typed Difficulty: Normal in the search bar but it doesn't seem to work, did I typed it in the wrong place?
I typed here:
https://i.imgur.com/siNIqHw.png
It also rest the options (Sort by, Over time period) to default when you search.