"My nephew has an easy work."
Translation:Nepotul meu are o muncă ușoară.
While understood, the sentence is poor english. I don’t know how to explain grammatically, so will resort an example!
"My nephew has an easy job" is OK. "My nephew has easy work" sounds clumsy, but it's meaningful in the sense that 'the work he carries out is easy'.
- but 'a...work' would never be used.