Shalom, If a person is going to be the officiant (Chazan) in a synagogue in which the Nusach of the synagogue is different from his Nusach, how should he proceed, should he pray according to his Nusach or according to the Nusach of the synagogue?
Thak you for youe question.
The rule with davening a different nusach then the congregation is that any part of davening that is said quietly such as the Shemona Esrei, may be said with one’s usual nusach. However the parts of davening that are said out loud, i.e. chazaras hashatz, kedusha, etc. have to be said like the nusach of the congregation.
Shulchan Shlomo (Tefillah) chap.5-19.