The Pri Chadash says that Goyim are Nikar and the Rash miKinon is also Mashma that way, don’t ask me how.
Minchas Yaakov and Kreisi u’Pleisi prove from here that Nikar is not necessary for Kavua. Kreis u’Pleisi also suggests that one indiviual anywhere in the world who knows makes it Nikar.
Also, Ma’adanei Yom Tov 7:20:70 quoted in Igros Moshe OC 1:178 writes that a Bar Da’as is automatically Nikar.
The Bach and Yad Yehuda understand that Nikar isn’t directly a Tnai in Kavua, it just prevents Bitul which would preclude Kavua.