How to trouble shoot alias in neovim setup

Question

I am following this tutorial to use lua in setting up nvim as an IDE. I am using Mac Monterey (12.2) and Z shell. The install has a script,

#!/usr/bin/sh

NVIM_BEGINNER=~/.config/nvim-beginner

export NVIM_BEGINNER

rm -rf $NVIM_BEGINNER

mkdir -p $NVIM_BEGINNER/share

mkdir -p $NVIM_BEGINNER/nvim

stow --restow --target=$NVIM_BEGINNER/nvim .

alias nvb='XDG_DATA_HOME=$NVIM_BEGINNER/share XDG_CONFIG_HOME=$NVIM_BEGINNER nvim'

This runs just fine and the install succeeds. I get my splash screen and nvim starts. the directory structure mirrors that in the tutorial and I can create files etc.

When I quit and restart the terminal, the alias - nvb for launching this 'new' nvim IDE is not found. I have looked at the alias. I don't know where it is writing the alias assuming thats the problem. I have a .zsh_aliases file pointed to using an entry in .zshrc which works fine normally. When I put the alias alias nvb='XDG_DATA_HOME=$NVIM_BEGINNER/share XDG_CONFIG_HOME=$NVIM_BEGINNER nvim' in .zsh_aliases or .zshrc it doesnt work.