#% chance to unnerve enemies for 4 seconds on hit, what procs it

I've seen people put unnerve on hit on hunter gloves, I am using ball lightning mine and the unnerve debuff would be great for me but I was unable to find on google whether mines can proc this.

What is considered a hit. I know fortify doesnt work vs all damage, just hit.

TLDR: do ball lightning mines trigger unnerve.

Yes - ball lightning is standard spell damage, not a DoT, so it hits.

The other question that always comes up is what counts as your own effect vs. an ally/minion effect. While a mine is distinct from you for some purposes, it does use your stats, buffs and modifiers. On hit/kill effects from your gear and passives should apply to your mines' hits and kills. (At least that's my memory from when I messed with mines...)