1. Nearest is used for place – it means ‘most near in space’
- Excuse me. Where’s the nearest tube station?
(not… the next tube station?)
- If you want to find Alan, just look in the nearest in the pub.
Next is usually used for time – it means ‘nearest in the future’
- We get off at the next station (=the station that we will reach first)
- I’m looking forward to her next visit.
2. We use next in a few expressions to mean ‘nearest in space’.
The most common are next door and next to.
- My girl-friend lives next door.
- Come and sit next to me.