It seems even the Internet has trouble finding a solution for this. Here's some from retropie and sixad that actually bypass the default bluetooth toolset and it actually works:
Reference 1(Part: For older versions of RetroPie) Reference 2
Ignore all the tutorials about using bluetoothctl, they won't work as the PS3 controller will keep connecting and disconnecting. You might managed to connect it using bluetoothctl in a Pi but definitely Nano is different.
- Start with sixpair, you'll need to do this usb-pairing first. Connect the PS3 controller via USB, you don't have to press any buttons yet.
wget http://www.pabr.org/sixlinux/sixpair.c