@d4hines it sounds like you only have joker defined in your path for interactive shells, i.e. when you run a terminal application. It is recommended to set PATH in shell configuration files that are sourced unconditionally (i.e. when run from the Mac OSX GUI launcher), such as .profile, .bash_profile or .zshenv.

# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/bin" ] ; then
    PATH="$HOME/bin:$PATH"
fi

# if running bash and .bashrc file exists, then read in the values
if [ -n "$BASH_VERSION" ]; then
    # include .bashrc if it exists
    if [ -f "$HOME/.bashrc" ]; then
	. "$HOME/.bashrc"
    fi
fi

When setting environment variables in .profile you will need to at least logout/login to the operating system (or restart) before those variables are picked up.

If joker is on the exec-path when Emacs has started and its still not working, then that is a problem. I would - check joker file is executable, eg. chmod a+x joker - delete the flycheck and flycheck-joker packages from ~/.emacs.d/elpa/<emacs-version>/<spacemacs-branch>/ and restart Emacs. Then Spacemacs will download the package again (sometimes a package can get corrupted when downloading) - update Spacemacs (I assume you are running develop, if not then consider using develop, as master is a long way behind) - update the packages using the Update Packages link on the Spacemacs home page and restart Spacemacs, SPC q r (and maybe restart a second time if there are more than a couple of package updates just to make sure).