I recommend ciognuen.
The sounds written in IPA (sans tones) would clarify exactly what is different:
- Standard Mandarin: /ʈ͡ʂʊŋu̯ən/
- Standard Italian: /t͡ʃoɲwen/
The choice of ci over gi is due to the fact that Italian does not have aspirated plosives, and Mandarin does not have voiced plosives. So in transliterating as close as possible to what is spoken, you also lose the contrast between initials like b and p as they both reduce to p.
The ng sound in Mandarin is an allophone in Italian as in the word banconota. The sound does not appear alone and cannot be written alone. So, the next closest substitute is the Italian gn.
The sound sequences can be found in native Italian words, so it should be fairly pronounceable to the Italian speaker: