Nasus Q does not provide 3 stacks from killing Gangplank's barrels
You gain stacks from last hitting Zyra's plants, wards, towers, clones, and Illaoi's hentai, but not when last hitting and killing GP's barrels. Its odd. also, Nasus's passive life steal works/heals him when he autos Illaoi's hentai. not on GP barrels. I don't know if life steal is supposed to work on things like Zyra's plants, wards, GP's barrels, Illaoi's tentacles, shaco boxes, heim turrets or other things with set amount of hits like blue wards and trinket wards and pink wards.