Canada has great homegrown software talent (mostly out of schools like UWaterloo and UToronto). They usually come to the US on TN visas, not H-1B.

Canada has given the US so many great people: Brian Kernighan, Alfred Aho, Rob Pike, Ken Iverson, James Gosling, Rasmus Lerdorf, Matei Zaharia, Geoffrey Hinton, Ilya Sutskever, Andrej Karpathy, John Chambers, Robert Gentleman...