Filming for the reality TV show, slated to debut Jan. 15, is under way north of Montreal.
TUF Nations pits four Canadian welterweights and four middleweights under coach Patrick (The Predator) Cote against Australian coach Kyle Noke's eight-man team.
The last man standing earns a contract to fight in the UFC, although traditionally more than a few others also move on.
The 29-year-old Johnson (19-10-1) is 7-2-1 in his last 10 fights, winning two of his last three most recently in the Maximum Fighting Championship. A welterweight from Burns Lake, B.C., he trains out of the famed Tristar Gym in Montreal.
The 32-year-old Taleb (8-2) also calls Tristar home. The Montreal middleweight is coming off a loss to Marius Zaromskis but won his two previous Bellator fights before that.
In August, Taleb took part in open tryouts in Indianapolis for Season 19 of "The Ultimate Fighter."
"I'm very analytical ... And I'm a striker,'' he said at the time when asked to describe his fighting style. "So I'm here to kick ass.''
Unbeaten Montreal welterweight Olivier Aubin-Mercier (4-0) trains at H20 MMA and Tristar.
A former member of the national team judo, he switched to MMA after seeing a GSP fight on TV while trying to learn English.
He has been training at H20 MMA for close to five years although he also spars at Tristar.
"He's one of the top guys in Canada now," said Richard Ho, Aubin-Mercier's head coach at H20 MMA.
The other Canadian welterweights are Matthew Desroches (4-0), of Fredericton and Chad Laprise (7-0) of London, Ont. Laprise also has a Tristar connection although he is affiliated with Team Tompkins as well.
Harris, a 36-year-old middleweight from St. Albert, Alta., with great submission skills, is another MFC veteran, winning two of three fights in the Edmonton-based promotion.
The remaining middleweights are Toronto's Elias Theodorou (8-0) and Sheldon Westcott (8-1) of St. Albert. Westcott has not lost since his pro debut in August 2007.
The Canada vs. Australia season follows on the heels of "The Ultimate Fighter: The Smashes,'' which aired last fall as a U.K. vs. Australia spinoff of the original series.
There have also been two all-Brazilian versions of the show.
Cote (20-8) and Noke (20-6-1) will fight in April after the series has aired.
Cote, a former middleweight title contender not campaigning as a welterweight, appeared on Season 4 of "The Ultimate Fighter," which featured veterans attempting a comeback.
Noke, who once worked as a security officer for the late "Crocodile Hunter" Steve Irwin, was on Season 11.
Coach: Patrick Cote
Olivier Aubin-Mercier (4-0), Montreal; Matthew Desroches (4-0), Fredericton; Kajan Johnson (19-10-1), Montreal; Chad Laprise (7-0), London, Ont.
Luke Harris (10-2), St. Albert, Alta.; Nordine Taleb (8-2), Montreal; Elias Theodorou (8-0), Toronto; Sheldon Westcott (8-1), St. Albert, Alta.
Coach: Kyle Noke
Chris Indich (6-1), Jake Matthews (6-0), Brendan O'Reilly (5-0), Richard Walsh (7-1).
Vik Grujic (6-2), Daniel Kelly (6-0), Tyler Manawaroa (10-0), Zein Saliba (4-0).