watch supports shell aliases if you put the following in your bashrc:
alias watch='watch '
You probably want to do the same for sudo.
alias [-p] [name[=value] ...]
[...] A trailing space in value causes the next word
to be checked for alias substitution when the alias is expanded.
For zsh you can create a global alias $=" " (I use $ because it is unlikely to be used anywhere but you can use anything and then just do watch $ myalias.
IIRC this doesn't work in bash.