Nail wrap and brush on super glue. You can buy plain self adhesive silk nail wraps from Amazon for about $5 for 40 precut pieces (Swiss Silk by Supernail). I use the brush on superglue from Stewart McDonald but you can use regular nail gel (also from Amazon for about $5). You can also get these things at drugstores or a big market with beauty supplies but they may not have plain stuff. If you like pink gel and little decorations though this was there when I looked.
Clean the nail with something like acetone (nail polish remover) or denatured alcohol. You can sand it lightly if you like to increase adhesion but I didn't. Choose a silk which is the width of the nail. Peel off the backing and stick it to the nail. Use a nail file or garnet board filing in a straight down direction to cut the end of the silk to match your nail. Sounds difficult but is simple and only takes a few seconds.
Brush on a coat of gel or superglue. It soaks thru the silk and bonds it to the nail very well. The gel takes 15 minutes or so to dry, the superglue about 2 minutes. Do second layer of silk the same way as a single layer is too thin. Then after that drys put on 2 more coats of superglue or nail gel to create a smooth surface.
Buff it with a nail polishing board and cut your nail as desired. It will look just like the original nail but will reinforce it and last probably several weeks to several months. Eventually it will become unsightly as the nail grows out or will simply fall off. Redo it after soaking the nail with a cotton ball wetted with acetone for a few minutes to remove the silk if it hasn't simply fallen off in the shower.
If this seems like too much trouble then just go to a nail salon and have a plain acrylic nail brushed on the existing nail. They use an acrylic powder and UV curing resin and it is very hard. Last time cost me $5 for 2 nails. This is thicker than the silk overlay however and may change your tone somewhat. The silk seems to work better. It reinforces the nail and makes it much stronger, something like a layer of fiberglass only very thin and invisible.
I will say that trying to do this to your right hand with your left hand is a little awkward. A helpful spouse might be useful but I managed it all by myself.