How do you know that Sodium Hydrogencarbonate is amphiprotic?
You have to consider whether or not the species is capable of both losing and gaining a hydrogen.

When sodium bicarbonate dissociates in water, it becomes a sodium ion ($\ce{Na+}$) and a bicarbonate ion ($\ce{HCO3-}$). The bicarbonate ion itself is what is amphiprotic, and this is because it can lose the hydrogen it has to become a carbonate ion ($\ce{CO3^{2-}}$), or it can gain a hydrogen to become carbonic acid ($\ce{H2CO3}$).

Many species that contain a hydrogen and an unbonded electron pair are amphiprotic, like $\ce{NH3}$ and $\ce{H2O}$, for example.