Nemo fuel level sensor issue

Could be a faulty sensor, they're not uncommon. Did the OBD reader give you a specific code?

It's showing P0460, 'Fuel Level Sensor Circuit Malfunction'. Does that point to the sensor itself rather than a wiring issue?

P0460 usually means the sensor is sending incorrect data. Wiring is possible, but on a Nemo of that age, the sensor itself is more likely. I'd get it checked at a workshop.

Took it to a local garage, and you were spot on. It was the fuel level sensor. They replaced it, cleared the code, and it's running perfectly now. Cost me about 52€ all in, including the sensor and labor.