Asked a Dr mate of mine and he said that they are not seeing any discernible impact from that- but long tenured EU nurses are leaving in large numbers, particularly Spanish nurses he noted (he had no idea why Spanish nurses were leaving in larger numbers, however).
Registration of new nurses from the EU since Brexit
https://www.health.org.uk/news/uk-public-support-recruitment-eu-nurses-post-brexit-including-leave-voters