But if you use an ability such as Nishaven's, Lightning Bolt, etc, it gains stats once a turn and takes no damage.

Text gives the impression it should gain stats on an opponent turn if they do...

Recently did a Nishaven mirror, only ally on board was my Goliath.
I used my ability, Goliath stats buff to 4 / 6.
Opponent Nish uses ability, no stat gain.
If intentional, card text needs...