Twenty-one-year-old Chettle, who joined Posh from Nuneaton Town, has found first-team opportunities limited during his time at the ABAX Stadium, making twenty-two appearances since joining the club two years ago without finding the back of the net.
He originally came through the ranks at Ilkeston FC under his father Steve, the former Nottingham Forest defender.
Chettle will be available for Saturday’s trip to Bromley.