MadFrog:

my training set is 800,000 rows and 153 columns.


800,000 would then be the batch size (or the total number of samples) while 153 would be the feature dimension.
In that case use
self.fc1 = nn.Linear(153, any_value)
self.fc2 = nn.Linear(any_value, 2)

The batch size is not part of the layer definition, as all PyTorch layers accept a variable batch size.
Your target should have the same batch size so you can calculate the loss using the model output.