I did not find it in homebrew and searching the web for solutions did not turn out anything useful for me.
My solution for you:
brew install icu4c
Read the message after install (nothing is at this moment direct available ...):
==> Caveats, This formula is keg-only, which means it was not symlinked into /usr/local.
brew list icu4c | grep uconv
And after all, here my example for using this tool for normalization (NFC) utf8 text:
/usr/local/Cellar/icu4c/55.1/bin/uconv -f utf-8 -t utf-8 -x NFC ~/Desktop/ue.txt | od -t x1