Forte's three goals helped County win their fifth game in six under manager Keith Curle.
With just 16 minutes played County took the lead when Alan Judge struck a perfectly-placed shot into the corner of Charlton goalkeeper Ben Hamer's net from 25 yards out and County doubled their lead with a superb counter-attack, which resulted in Forte tapping home from seven yards.
A mix-up between Addicks defender Matt Taylor and Hamer in the 35th minute saw Forte sneak in and prod the ball over the goalkeeper's head for County's third and the striker headed past Hamer for his hat-trick in the 40th minute.
Bradley Wright-Phillips gave Charlton a glimmer of hope when he hooked home Scott Wagstaff's cross five minutes after the interval.
The Charlton striker repaid the favour in the 55th minute when he crossed for Wagstaff to head Charlton's second from close range.