Thorne, who was with the Silkmen on non-contract terms in the 2014-15 season but did not feature, has been playing for Forest's development squad.
The 21-year-old made his Forest debut in this season's EFL Cup win at Millwall in August.
He is eligible for Macclesfield's FA Trophy fourth round tie against Dulwich Hamlet on Saturday.
Nottingham Forest have loaned forward James Thorne to National League side Macclesfield Town on a one-month deal.