Yes, you can! I've been wearing nose studs for a while in my ear piercings, and I find them very comfortable. I wouldn't recommend doing this with an L-bend unless you plan on wearing an o-ring with it, but nostril screws make very secure pieces of ear jewelry. If the nose screw fits well, the charm will sit flush against the front of your earlobe and the curl of the screw will also sit flat against the back of your ear.
The only drawback to wearing a nose screw in your ear piercing is that you need to either have a caliper on hand to measure how thick your earlobe is, or be willing to go into a piercing shop to ask someone to measure your ear for you.
The rise (the part that actually sits in the piercing, not the curl) of the nose screw needs to be a custom length made to fit the thickness of your earlobe. To have the jewelry work properly in an ear piercing, it's very important that it hugs the ear closely - a loose piece, one where the rise is too long for your ear, would easily to snag on hair and clothing.
If you don't have access to a caliper, or feel comfortable asking a piercer to measure for you, a slightly less accurate method of measuring how thick your earlobe is requires a plain stud earring, a fine tip marker, a ruler, and a friend to help.
Another consideration that you should keep in mind is which way you want the bend to curl on the nose stud - do you want the back of the nose screw to curl pointing at the back of your head, or the other direction toward your face? On the right ear, a left bend will curl toward the back of the head, and a right bend will curl toward the face. On the left ear, a right bend will curl toward the back of the head, and a left bend will curl toward the face. The direction of the bend really only matters if you have multiple earlobe piercings - you don't want the curl to get in the way of your other earring backs.
Interested in trying out a nostril screw in your ear piercing? I can customize the length on any of the nose studs that I make so that they fit you perfectly. Browse available nose studs here: Gold Nose Studs and Sterling Silver Nose Studs.