Guys, thanks for your help.
In fact my issues were:
I was using the same MISO and MOSI pins for both LiquidCrystal and nRF (because ICSP MISO and MOSI are internally connected to digital pins 13 and 12)
Also, my LiquidCrystal is not operating on ISP mode, so different pins are needed indeed. I've changed the Display pins 13 as 12 to 10 and 9 and now this part of my project works!
Thank you
Sorg