Belper boss Grant Blank said Nyoni would help give his side some different options.
“He is a great addition for us,” he said. “He is different to what we have in midfield and offers another great option.
“He’s big, strong, physical, athletic and runs hard with the ball.
“We are really happy to get Cecil sorted. He’s a great character and will offer the kind of personality we want associated with Belper Town.”
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Nyoni added: “I believe in the project that he club is building and the manager is striving towards.
"I just want to be part of this great plan that you’ve got in place and showcase what I can do as well.”
Nyoni joined Sheffield Wednesday just before his 16th birthday, making his professional debut in 2011 in a League Cup tie with Blackpool.
He then went on loan to Boston United before signing for Frickley Athletic on loan for the rest of the season.
Cecil joined Nottingham Forest during the 2012–13 season, before joining Worksop Town on loan for the rest of the season.
He had spells at Matlock Town, Stocksbridge Park Steels, Harrogate Town, Alfreton Town, Gainsborough Trinity, Shaw Lane and Worksop Town again in 2018.
He joins strikers Damian Reeves, Andre Johnson and Jonathon Margetts, Goalkeeper Myles Wright, midfielder Morgan James (Midfield) and defender Tyler Williams as some of the club’s new faces for next season.