nix command not found in tmux panes and windows

I use nix and home manager, zsh and tmux. My problem is that in tmux splits the nix command does not exist. I tried setting default shell in tmux to /bin/zsh -l sourcing files etc, I notice the PATH is just missing /nix/var/nix/profiles/default/bin:/Applications/Ghostty.app/Contents/MacOS My .zshrc has

if [ -e '/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh' ]; then
  . '/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh'
fi

I tested this in different terminals too - same story.