Yes, you can connect the (-) cable to the donor car's chassis. There may be some additional resistance, but it should work fine. Make sure that the last connection you make (of the four, two on each vehicle) is as far away as possible from the battery in that vehicle.
You're providing a current path from the donor battery to the recipient battery. The donor ...
Yes there will be extra electrical resistance, but this will be negligible compared to the extra cable length used in the jump cables.
As long as the connections are secure and not on painted surfaces it will work fine.