The 23-year-old – who played Weatherfield hairdresser Candice Stowe for six years before quitting after feeling sidelined by producers – will play the role of Dawn Bellamy, niece of the now-dead Phil Bellamy (Mark Jordan).
She arrives in Aidensfield on an extended holiday, having been sent by her worried father (Phil's brother) who fears that his daughter has become involved with the wrong crowd in Manchester.
Dawn will earn her keep behind the bar at the Aidensfield Arms, while keeping her 'auntie' Gina (Tricia Penrose) company following the tragic loss of her husband. Oscar (Derek Fowlds), meanwhile, is afforded the task of keeping her on the straight and narrow.
Though Dawn has the best of intentions, she spends her time dreaming of a glamorous career down South.
Speaking of her new role, Sanderson said: "I'm so excited about starting on Heartbeat and meeting all of the cast. My family and I have always loved the show, and I can't wait to put on the '60s clothing."
Heartbeat producer Archie Tait added: "Nikki will be a fantastic addition to the show. Dawn is a great character who is certain to spice things up in Aidensfield."
The actress begins filming in Yorkshire at the end of this month and will first appear on screen later in the year.
Earlier this year, Sanderson shelved a reported Corrie return intended to tie in with Tina O'Brien's departure. She was also rumoured to be in the running to appear in the new series of Dancing on Ice.