When you install fzf (e.g. brew install fzf), you can also install
completions and a few keybindings by running the /usr/local/opt/fzf/install
binary.
Included with the keybindings is Alt+c which opens an fzf prompt for the
directories nested under your current directory. You can type into the prompt
to narrow down the results with fzf's fuzzy-finding capabilities. When you see
the directory you wan, you can use the arrows to navigate over it and then hit
end. You'll be cd'ed into that directory.
On my Mac, the Alt key is the Option key. Hitting Opt+c outputs the ç
character instead of opening this fzf prompt. It turns out, you can
alternatively hit Esc+c to trigger this prompt.