same meaning so you can exchange each other.
but "nante" is a slightly polite or elegant expression.
these two words are spoken words (non literary words).
and often use sometimes to despise something, i think.
i hate you
anata nante kirai
anata nanka kirai
anata ga kirai
i love you
anata nante suki (inappropriate)
anata nanka suki (inappropriate)
anata ga suki
is this answer you want? there is some typyes of meaning and using both "nante" and "nanka".
if its not, write sentences you confused.