Based on the stoner term weaksauce, nubsauce is directedly more specifically at a person who completely fails at life. Usually tossed around in online circles, it denotes somebody who is not just a noob, but is completely lame as well.
Dude, GenericH4x0r is nubsauce.
Dude, why you gotta be like that?
Don't talk back to me nubsauce.