You can cut sim cards to make them fit. Going to a nano sim requires a little bit of sanding to make it more slim, but I've done it a number of times and never had a problem.
There are PDF templates that you can download and print to help you with where to cut, and there are an endless number of YouTube videos about how to do it.
Or you can buy a sim cutter if you're not feeling comfortable with using scissors. http://www.amazon.com/Fosmon-Nano-Micro-Nano-Standard-Micro-Standard-Adapters/dp/B00AR1V1WS/ref=sr_1_2?ie=UTF8&qid=1442249978&sr=8-2
Nano, and you can cut it, but if you don't have a nano to use a template, use a SIM card cutting tool from Amazon.
Keep in mind you'll only get one chance to cut this, so be careful! :)
When I switched from my Note 4 to my Nexus 6, I actually bought a cutter off amazon and just cut my sim card down, and it works fine.