The former United midfielder, who retired at the end of last season, flew out to Hong Kong at the weekend to weigh up the merits of the move, and could stay for the rest of the season.
The 35-year-old, who won six Premier League titles with the Reds, has spent the past few days training with South China in preparation for the game against local club TSW Pegasus at the Hong Kong Stadium.
"I'm very excited to come over to South China to play football," Butt told a press conference on Monday at the city's harbourside Grand Hyatt hotel, where he was handed South China's no.12 shirt.
"I've experienced a lot of things in my football career, I've had a lot of highs. Hopefully this will be another one.
"This is a new country for me and an exciting place... I can bring my children here. It ticks all the right boxes. I'll have a decision over the next two or three days."
South China FC chairman Steven Lo, a prominent Hong Kong businessman, hopes players of Butt's calibre will help South China take the coveted AFC Championship early next year.
"We have high expectations for Nicky. He is a very experienced star at a very high level," Lo said.
Watch out for an exclusive diary with Nicky on his first days in Hong Kong, coming soon to ManUnited.com.cn.