Well, KING-TV had Bill Nye before the Science Guy back in the late 80’s. He was a cast member on Almost Live back then. (If you don’t know of Almost Live, I recommend you YouTube it.)
From there, he went to the folks at KCTS and came up with the idea of Bill Nye the Science Guy in 92 or 93 I think. It was always on KCTS at the beginning. Apparently it was a syndicated show for a year, but I don’t remember it on anything but PBS.