Twenty-two-year-old Schonert, who was part of South Africa's IRB Junior World Championships side in 2011, is known for his physical presence and technique at the set-piece and is regarded as one of the most talented forwards in his country.
He represented the province of Kwazulu-Natal as a youngster before stepping up to play for the Sharks at Under 19 and Under 21 levels.
In 2012, Schonert moved to GWK Griquas and played in the Vodacom Cup and Currie Cup before joining Super 15 side Cheetahs at the start of this season.
Schonert said: "I was so excited when I got the call from my agent informing me that Worcester were showing a lot of interest in me.
"After Dean Ryan flew over to meet me and explained the vision for the future, I knew I was going be a part of something special.
"One of my best friends Mike Williams is also at the club and, having played over one hundred games with him, I knew the club would be filled with good players. I am very excited about my future at Worcester."
Dean Ryan said: "I am delighted that Nick has decided to move to Warriors. He is aware of our long-term focus and is committed to being part of our journey.
"Nick is the sort of player who will add to this club and he has the potential to be an outstanding Premiership player so we are looking forward to welcoming him to Sixways."