Thank you for the post. I will forward your inquiry to the board support for them to better assist you. thank you.
All the shields that have been tested are documented in the Shield Test Report Unfortunately the NRF24L01 is not one of them. There is a project using the nRF24L01 with a Galileo so It's possible.
Also; take a look at this thread Issue compiling with nRF24 Lib We have been trying to change some things in the libraries to make it work in the Edison you could try to do the same with your Galileo
You could use the libraries from here: maniacbug/RF24 · GitHub