@soward Power and cabling has been checked. All is fine but I still get that error.

I checked Voltage which is fine. Also Nano is working fine (Blink etc). I actually tested with three different nano and all give me same result whereas the UNO's immediately work. Do I need to make any adjustments in the code if I use Nanos?

I am building a motion sensor connecting to my ethernet gateway. When I make the sensor with Arduino Unos it works great. If I use same radio, sensor, cables and code with Arduino Nano's I get an "radio init fail".

I triple checked cabling, the nanos etc. Also put a capacitor etc. but no success.

Anybody has an idea why it works on UNOs but not on Nano's?