According to this A330 call panel diagram, there is an option to call the nose gear bay with the MECH button. Where is the connection for this in the nose gear bay, and what would it be used for? The closest I can find is in this video, where some connections to call the cockpit of a Boeing 777 are shown in the forward avionics bay, presumably to help with communication among maintenance personnel. Whether these jacks are similar to the MECH channel on the A330 I do not know.
The fact it's called the MECH channel is a pretty big hint that yes, this is for maintenance personnel.
Ant it's not just the nose wheel bay, there are service interphone connections in several locations.