I'm a novice at chemistry. I've heard that an acid needs water to show its acidic properties, that's why nitric acid needs to be associated with water to show its acidic properties:
$$\ce{HNO3 + H2O <=> NO3- + H3O+}$$
$\ce{H+}$ does not exist freely and is always associated with another molecule like $\ce{H2O}$.
But then you would expect that the hydroxide anion would need to associate with water to show its basic properties. However, reactions never show that. In the case of sodium hydroxide, it just shows the $\ce{Na+}$ cation and the $\ce{OH-}$ anion dissociate in solution. But by that logic, nitric acid in water should be $\ce{NO3- + H+}$, which shouldn't be the case.
Why does $\ce{H+}$ need to associate with $\ce{H2O}$ to become $\ce{H3O+}$, but $\ce{OH-}$ can remain as it is and not as
$$\ce{NaOH + H2O <=> Na+ + H3O2-}?$$