23-year-old Nizzolo will ride for the team until 2014, while veteran Popovych commits until the end of 2013.
Italian Nizzolo joined the team in its guise as Leopard Trek in 2011, and this year finished first overall in the Tour de Wallonie, as well as winning his first UCI World Tour stage at the Eneco Tour.
"I'm pleased to stay in the team where I have gotten the chance to grow as a pro bike rider," Nizzolo said.
"My victories in the past weeks were reassuring for all parties: some sprints were won with amazing support of the team, others were necessarily done with fighting my way to the finish line, but that's life for a sprinter. I'm hoping to step up now and return the faith the team has given me with some nice results."
Popovych, who hails from Ukraine, has ridden for a host of teams under manager Johan Bruyneel, and has three top 10 finishes on Grand Tour General Classifications.
"This team is pretty much like a second family for me," the 32-year-old said.
"I know a lot of riders and staff since years and I've gotten to know a lot of new faces over the last year. I feel very good in this team, so there's really no reason to consider to change."
"I'm really happy and proud with both renewals," added Bruyneel.