doing repairs will depend on your skills - do you do all systems - if you do, then do a fibreglass wrap on the cracked nail, if not then overlay with whatever overlay product you use. I don't think a broken nail will survive with just adhesive.
I usually lightly buff the nail near the place where it is broken, clean off the dust and glue (regular nail glue) on a tiny piece of fiberglass. Once the glue dries, i lightly buff over the glue so that the fiberglass ridges no longer show. After applying polish (even clear) you can hardly tell that there's anything on the nail.