Feeling curious to see if I could update the election nowcast myself, I had a go at building this package from the source code and it turns out line 8 from https://github.com/ellisp/nzelect/blob/master/build.R below fails:
devtools::install_github("nz-mbie/mbiemaps-public/pkg")
because the nz-mbie/mbiemaps-public (and in fact, all repos under nz-mbie) has been deleted. It looks like MBIE has taken down all of its public github repos.