If the story about NZF being in touch with Tyler Boyd is true then it makes sense that they would also have been in touch with Niko and others. Especially since Niko is probably required to declare for NZ given he is also eligible to play for Italy. Niko telling someone about getting such a call is the only way I can see that story having come about, unless a journalist in Venice somehow has a contact at NZF.
If the story about NZF being in touch with Tyler Boyd is true then it makes sense that they would also have been in touch with Niko and others. Especially since Niko is probably required to declare for NZ given he is also eligible to play for Italy.