I came across this video recently:
https://www.youtube.com/watch?v=FpJpj8irbUc&The narrator mentions that, apparently, there were some scenario maps for Brood War in which Tychus plays a role. Does anyone know if that is true and, if so, where one can find these maps?
None.
There are no BW scenarios with Tychus which are regarded canon, since Tychus is an SC2 newcomer and didn't exist before it's scenario started to be developed. There are some fan-made things, I can recall one such map, but they are obviously not canon.