Decoder installed?

You did not mention whether the locomotive has a decoder installed or if the nose headlight had a bulb or LED installed in it. Assuming that the locomotive runs well on the NCE controlled track, it has a decoder installed so the next issue is whether the nose light has a light source (bulb or LED). If not, you will have to install one.

Then determine if the nose light is to run with the headlight function --F(0) or if it is to be a warning light like a Mars light which might run on another function like F(3) or F(5). You will have to determine what kind of decoder is in the Atlas locomotive and then wire the nose light to the proper points on the decoder for either a headlight or warning light and program it accordingly.

Not knowing the decoder installed is a big problem for further analysis and help. Were there not instructions with the locomotive?

John