Yeah, just make sure it's .3 ohms worth. Even with real nichrome it's kind of a crap shoot as to what the hot resistance is going to be. You want to calibrate it - the voltage is easy enough to measure, but trying to get the current is going to be tricky. Most meters don't read that high, a clamp-on DC ammeter would do it, but it's more expensive than the AC version. Once you have the loaded voltage across the steel bar and the current running through it, you can divide the former by the latter and find the actual resistance at the working temperature.