Using PEX Fittings with Nylon Tubing
There is a great video on YouTube by "The Build Show" about various PEX and push to connect fittings. They pump them up until they burst. They burst well above the stated ratings. Unfortunately I can't answer the nylon pipe question but check out the video

The Build Show with Matt Risinger 14,000 PSI test 

I temporarily installed PEX Airlines and PEX oil line for my best friend who is a mechanic and that was four years ago.