How to fix my broken Nikor lens?

I had my Nikon camera around my neck while vacationing in Switzerland and after bending over to pick something up on the floor of the train, it slipped off and fell. The camera body is fine, and the lens still works… However the part that holds the lens into the body is broken so I've got to hold the lens in place to operate the camera. I'm wondering if there's any way to fix this myself, or what the cheapest repair route would be if I can't. Any advice would be greatly appreciated!

The best thing to do is send the lens into Nikon for a repair estimate. Depending on which lens it is, the repair and adjustments/calibration needed from being dropped might be cost prohibitive.

Camera repairs are not a do-it-yourself type of project. They are better left to trained technicians.
Take the lens to a Nikon dealer for assessment and/or repair.