Leeds striker Ross McCormack and Blackpool goalkeeper Matt Gilks have been recalled to Craig Levein's pool for games against Wales and Republic of Ireland in the biennial tournament which also includes Northern Ireland.
"Russell has had a fantastic season at Norwich City, and congratulations to Paul and his backroom staff and players for getting promoted to the English Premier," Levein said. "Russell is one we have had our eye on for a while. He's in the squad but there are still elements of the paperwork to be finalised.
"If we can't get it done in time, so be it, but I'm confident. His father is Scottish so it shouldn't be too difficult. Norwich have been in the States celebrating and he has flown back early to get the paperwork done."
Wolves in-form striker Steven Fletcher's international exile continues, while Levein was unable to call up the injured Alan Hutton, Craig Gordon and Graham Dorrans. Fitness reasons have forced Mark Wilson out and Darren Fletcher is unavailable because of Manchester United's participation in the UEFA Champions League final.
St Johnstone midfielder Murray Davidson and Watford's Don Cowie have dropped out of the squad following the defeat by Brazil in March, while Kilmarnock captain Craig Bryson and in-form Motherwell wide player Jamie Murphy have missed out.
Peterborough striker Craig Mackail-Smith is in the squad after making his debut against Brazil, although his presence will depend on the outcome of the League One play-off semi-finals.
The tournament takes place from 24-29 May.
Scotland squad for the Nations Cup:
Goalkeepers: Matthew Gilks (Blackpool), Allan McGregor (Rangers), Iain Turner (Everton);
Defenders: Phil Bardsley (Sunderland), Christophe Berra (Wolves), Gary Caldwell (Wigan), Stephen Crainey (Blackpool), Grant Hanley (Blackburn), Russell Martin (Norwich), Steven Whittaker (Rangers), Danny Wilson (Liverpool);
Midfielders: Charlie Adam (Blackpool), Barry Bannan (Aston Villa), Scott Brown (Celtic), James Forrest (Celtic), James McArthur (Wigan), James Morrison (West Brom), Barry Robson (Middlesbrough), Kris Commons (Celtic);
Forwards: Craig Mackail-Smith (Peterborough), Chris Maguire (Aberdeen), Ross McCormack (Leeds), Kenny Miller (Bursaspor), Steven Naismith (Rangers).