It wasn’t one legion general, but by all means continue lying.
Guldan
Chogall
Mannoroth
And still you blithely ignore that they not only defeated them, but stole their power so that they could use the dark portal.
Or, what
Did you not notice that the iron Horde had no warlocks?
Do you think any of us think you’re that blank? Nah, homie. We know you’re lyin’.
I think it really depends on how you look at the situation.
Did the Iron horde beat a full sized Legion assault/invasion? No.
Did they trivially beat the Legion forces that did show up and kneecap their ability to summon in reinforcements until the Azerothians decided letting Gul’Dan waltz off a free orc was smart? Yes.
We know that the Legion takes ages to invade lands if they don’t have a foothold in to summon in their big boys. An allied Orcish/Draenic force could have probably prevented any of those footholds being established if all went right.