If Type is set to From Output, then the dialog will look as shown below.
This browse button will allow you to load the result file (*.FNO) and use the currently loaded results file as the input for a load. Currently only temperature output is supported in the Nodal Load drop-list. You can select the output set you want to get the nodal data from, and the subcase you want to add the load to. The temperature from output load can only be applied in a structural analysis.
An example of using this load type would be to run a heat transfer analysis, then take the resulting temperature distribution and apply that to a structural analysis to see the thermal expansion effects.