Thanks for asking :) They are two separate concepts.

Neurodiversity is the idea that we need changes and differences in our neurotypes for the health of humankind (a la biodiversity & evolution).

It also refers to a political movement in which we who are neurodivergent are trying to educate others on the fact that our disabilities often come from a lack of understanding, knowledge, acceptance, and accommodation by the general public, rather than from our divergent neurotypes themselves.

Neurodivergence is the fact that brains are divergent from the statistical norm.

So you can't have neurodiversity because that requires multiple brains, but you can be neurodivergent if your neurotype is outside of the statistical majority.

I hope that helps