The 28-year-old joined the Spireites on a one-year deal in June and has scored seven goals in 24 appearances for the struggling club.
Four months after signing at the Proact Stadium, Evans was found not guilty, following a retrial, of raping a 19-year-old woman in a hotel room in 2011.
He was initially found guilty in 2012 and served two-and-a-half years of a five-year prison sentence, but his conviction was quashed in April 2016.
Evans told the club website: "I'm really pleased to have got this sorted out. I want to play well and score as many goals as I can between now and the end of the season to help us get out of the relegation zone."
The forward, who played for Manchester City, Norwich City and Sheffield United before his time in prison, has won 13 caps for Wales but has not featured for the national side since 2011.