Complex sentence: Nasri Atweh is also a renowned songwriter and producer who is part of The Messengers, a duo songwriting/producing partnership with Adam Messinger with a string of hits for well-known artists.
Split into simpler sentences: Nasri Atweh is also a renowned songwriter and producer, one half of the songwriting/production duo The Messengers. He and Adam Messinger have a string of hits for well-known artists.