Kinghorn's knee injury meant he missed the opening two games of the championship – a narrow 27-26 win over Wales and a 20-16 home defeat by France – forcing coach Gregor Townsend to use wing Kyle Rowe and uncapped Harry Paterson in the number 15 jersey.

Nel, a key part of the Scottish scrum for the best part of a decade, is also fit again and could play for the first time this year after overcoming a neck injury. He replaces Javan Sebastian in the squad.

Watson was left out for the first two matches of the campaign as Townsend cast his eye over other back row options, but a concussion injury to Josh Bayliss means a recall along with flanker Magnus Bradbury.

Wing Ross McCann drops out of the squad but there is no return yet for injured Darcy Graham, who remains sidelined with a groin issue.

Updated Scotland squad:

Forwards: Ewan Ashman, Magnus Bradbury, Jamie Bhatti, Alex Craig, Andy Christie, Scott Cummings, Jack Dempsey, Rory Darge, Grant Gilchrist, Matt Fagerson, Zander Fagerson, Alec Hepburn, Johnny Matthews, Elliot Millar-Mills, WP Nel, Jamie Ritchie, Pierre Schoeman, Sam Skinner, George Turner, Hamish Watson, Glen Young

Backs: Ben Healy, George Horne, Rory Hutchinson, Huw Jones, Blair Kinghorn, Stafford McDowall, Harry Paterson, Ali Price, Cameron Redpath, Arron Reed, Kyle Rowe, Finn Russell, Kyle Steyn, Ross Thompson, Sione Tuipulotu, Duhan van der Merwe, Ben White.