I live in Nelson. There are some good breweries here but also good bars which have beers from around the country as well.
Hop Federation, Mussell Inn, Golden Bear, Eddyline (Colorado franchise), Sprig and Fern, Townsends are all good. Nothing spectacular though.
Peckham Cidery does amazing old world ciders if you're into that.
Best craft bars are Freehouse, Craft Beer Depot, and the workshop.
If you're in the region let me know and I'll show you round.
If you're looking for best craft bars, Wellington wins hands down.