Have a look at this Simple nRF24L01+ Tutorial.
Wireless problems can be very difficult to debug so get the wireless part working on its own before you start adding any other features.
The examples are as simple as I could make them and they have worked for other Forum members. If you get stuck it will be easier to help with code that I am familiar with. Start by getting the first example to work
I have never tried to get an nRF24 to work with an ESP8266 but the idea of getting the nRF24 communication working in its simplest form still holds.
...R