Actually you could be right - I just saw that Illy has nespresso compatible capsules, and CX removed the Nespresso logo from their menus a while ago.
I might need to buy some of these capsules to try myself.
Sorry I'm all over the place with my facts today. The illy capsules are not compatible with nespresso machines, so I doubt that CX is using them unless they have a special batch that can be used in Nespresso machines. CX was definitely using Nespresso previously, so I doubt they would have removed the machines and replaced them at great cost, since these aircraft models are expensive.
Promise I'll try and remember to check on my next flight! To be honest I am happy with both as Illy (indeed, different machines) and Nespresso both make very decent coffee by airline standards!