There is a big difference between what the Constitution grants to the federal government, the very specific power to “To establish an uniform Rule of Naturalization,” and the broad extension to policies that have nothing to do with immigration. All other powers except those enumerated in the Constitution are with the states, and the people.
That part of immigration which is allowed is the part that deals with naturalization. The illegal entry and presence of aliens in the US is not a naturalization process, unless you believe that an illegal alien is accomplishing his first step to naturalization, in which case the whole world will sneak in here illegally to get naturalized.
Getting employment is not part of any naturalization process.
Do you really want the individual states to set their own unique immigration policies? Tell me, what do you think states like California would do with that green light? Sanctuary cities are bad enough. Sanctuary states?
By the way, it seems to me that this ruling pulls the rug out from under those sanctuary cities.