The Northern Irishman is currently No.2 to Paul Hartley at Falkirk but will leave the club after Tuesday’s clash with Dunfermline.
Graeme Murty has been looking to add to his coaching staff since being named as the successor to Pedro Caixinha as manager of Rangers until the end of the season.
Nicholl, 61, had two spells at Rangers during his playing days and has picked up a wealth of coaching experience since then.
He’s managed Raith Rovers on two separate occasions, including leading them to a 1994 League Cup final triumph over Celtic, while also spending time in charge of Millwall and Cowdenbeath, along with caretaker stints at Dunfermline and Hibs.
He has also been part of Michael O’Neill’s backroom staff with the Northern Ireland national side since March 2015.
His duties with Northern Ireland once saw him miss a clash with Rangers at Ibrox while he was manager of Cowdenbeath. Assistant Lee Makel took charge of the game, which the Blue Brazil lost 4-1 on their way to relegation from the second tier.