Welcome to the forums!
eBird is showing a few records for Port Hardy but I think it is uncommon for American Goldfinch make up to the north island. Here in Victoria, they are common and all over the place right now. There seems to be a few recent (last few years) sightings/reports of Goldfinch at the Port Hardy airport.
https://ebird.org/map/amegfi?neg=true&e ... =12&yr=cur
The coast mountain range may be a barrier for many goldfinch as the map suggests they range up through the Comox Valley but don't make it past Campbell River.
Based on eBird reports, North Island may not be as well covered (birded) compared to the inner coast from Campbell river down to Victoria. They may be more American Goldfinch occuring that we don't know about yet . Also, Goldfinch like weedy fields, cultivated areas, roadsides, orchards, and backyards. As more areas in North Island are cleared for farming, this will make the area more attractive to goldfinch.
To help out the science community, you might want to create an eBird account and report the Goldfinch sighting and other species you are seeing at your home. This helps the birding community understand what is occurring in your area and who knows, maybe data you contribute will help redraw the range maps for some species or not trends like Goldfinch this year and maybe again next year and in future years (means their range is expanding). It is neat to be a part of this and lots of opportunity in places where there are not a lot of bird watchers.