NKJV is more readable for people who grew up reading blog posts instead of old books and generally retains the poetry of the KJV, but it's under copyright. I think it would be allowed for a use like this though, because they explicitly allow (as do most translations) quoting up to a certain number of verses.

EDIT: Maybe not, here's the rules: https://www.harpercollinschristian.com/sales-and-rights/perm...

Seems like you'd fall afoul for the % of total text requirement.