You’re going to need some sort of lock in device to do nose grinds. I use an Iron-type device I made, but any sort of nubs or udders will work.
I prefer to do the trick frontside, coming in on my toes.
The biggest part of nose grinds is when you ollie, you need to get your weight up on to your nose. When you pop, lift up your back foot and bring the board up and over the box, on to your nose.
Once you are on the rail, try to stay balanced over your nose.
As you come off the rail, you want to try and pop a little bit off your nose. The most important thing is to not drop your tail as you are coming off. This will take some practice.
You can do this trick backside, coming up on your heels. This is similar to a backlip, but a little bit easier as you don’t have to get all the way over it. You can also do crooked grinds or over crooks by angling your board either way over the rail.