Absolutely not. Quite some dumb idiotic arguments suggesting she could as well.
1. Gamora has already said she doesn't know if it's possible to kill Thanos. Her trying to kill him doesn't mean anything when she's flat out said she doesn't know if it's possible. What do you think makes these people heroes anyway?
2. The entire scene is an illusion and in this illusion she hacks him in the face with the sword and nothing happens. Can't take that scene seriously.
3. Iron Man's attack was a blunt force/energy attack. Not comparable.
4. Thanos was no-selling slashes from Strange's magic swords to the back, caught the sword in his hand and then broke it. Drax couldn't pierce him either. Bucky's gun's also couldn't pierce him.
5. The only that that's pierced him that's comparable to swords and whatnot is Stormbreaker and Thor literally calls it a "Thanos killing weapon". Couldn't be more obvious you need OP ass weapons to kill Thanos.
So no, she could not pierce him. In fact, I'm pretty sure the only thing that will kill Thanos in the MCU is all 6 Infinity Stones being used on him.