You can't spoof it directly by just putting your phone over the Switch Joycon, but you are able to spoof Amiibo's using an Android device or any device that is capable of writing data to an NFC215 chip.
The process is relatively simple and if you have a phone that can do it then you will be able to do this cheap and easy. I have created a detailed guide with pictures on how to spoof Amiibo's using an Android device.
