Walker, son of Reds legend Des, made his Forest debut in March and the 18-year-old scored his first senior goal in the draw against Brentford in April.
Forest's teenage Swedish goalkeeper Tim Erlandsson has also penned a three-year professional contract with the club.
The 18-year-old spent last season in Forest's successful Under-18 team while on loan from Halmstads BK.
Nottingham Forest striker Tyler Walker has signed a new four-year deal with the Championship club.