Chamanga made his international debut on 26 February 2005 against Botswana and five months later he scored his first international goal in the COSAFA Cup semifinal against South Africa. His goal against Bafana Bafana earned him his first move abroad as the then South AfricanPremier Soccer League side Bush Bucks signed him in 2005. After Bush Bucks were relegated in 2006 he signed with Supersport United where he was the club's top goalscorer for the 06/07 season.
He was part of the Zambian 2006 African Nations Cup team, who finished third in group C in the first round of competition, thus failing to secure qualification for the quarter-finals. He netted Zambia's opener against Sudan (2008 African Nations Cup) in the Chipolopolo's 3-0 win. Chamanga also scored Zambia's first goal at the 2006 African Nations Cup against Tunisia.
He scored a record-breaking five goals for Swallows in a 6-2 league win against Platinum Stars on December 9, 2007. This included a hat-trick between the 20th and the 24th minute.