Nose slides are pretty hard. A curb will do fine for this grind. Gain some speed, ollie, turn something like 65 degrees and land the nose on the curb. Your leading foot should be on your nose. Now, lift up your trailing foot a little and let yourself slide. When you think you slid enough pivot off and land.
Hints: If your having problems landing the nose on the curb try stalling. Just stand next to the curb, ollie, turn something like 65 and land the nose on the curb. Stay on the curb for a few seconds, pivot off and land. Do that a few times and you'll be able to do the real grind perfectly.

Trick contributed by: www.skateboarduk.com