Sorry in advance for my poor technical knowledge, we just started using CNC Lathes. Here goes:

The company I work for just bought an NL 3000 long bed. Operators have been running it for two weeks with no problems then over the weekend one operator forgot to put the minus sign when setting tailstock for new length and it over traveled and "timed" itself out. Nothing will move, no alarms are being shown, and the we broker we bought it from has no idea how to fix. Tried moving tailstock by adjusting ball screws but they were tight. Is there anything we can do on the controls to reset it?

Look for an overtravel release button, on mine it's by the serial connection. Also you might be able to unbolt the limit switch if you can get to it.

There is no over travel release button on a NL lathe.

Go to the tailstock settings page and change the approach and thrust positions so there is a large difference between the two. Then you should be able to use the jog mode to move the tailstock.

The tailstock on an NL should be zero returned using a G28 G59 B0. Just make sure the G59 B value is zero.