If we ever do reset the nether, yes the world will regenerate. Again we don't plan to reset the nether but I can't say we NEVER will.
2 main reasons we would reset the Nether map:
1) Resources are drained and players find it hard to get soulsand / quartz / glowstone
2) Mojang releases an update that changes Nether map generation. (The way 1.8 added ocean temples to the overworld - only way to take advantage of the new content is to regenerate the map)
Since neither of the above is a problem right now - no plans to reset the Nether now.