Recheck all your Nano connections. I think you still have the pin numbers and names mixed up. You will see almost all designs reference the pin name, because that ties back to the function in the microprocessor.
Your IRQ should be D2 for example.
Grab a Nano pinout from the web. You want to align the CSN, MOSI, MISO, SCK, to the corresponding digital pins for the Nano. You will also see pins with functions INT 0 and INT 1 Your IRQ has to go to one of those.
Look at the MySensors "How to wire the radio" page. It has the pins that are most normally used.
Welcome to the club. You can do some pretty amazing boards in KiCAD once you get the hang of it.
PS. If you are in the US, check out oshpark for some prototypes. 3 boards for $9 if they meet the size requirements, and they are faster than delivery from China.