Hey, thank you so much for all explanations here @KFrank and @ptrblck !!!
I was performing some tests using tensors with lower dimensions to ensure that the loss result is correct and, due to this,  expand to tensors with higher dimensions and do not worry about the possibility that the loss value is wrong.
I was actually using nn.CrossEntropyLoss () in the wrong way, I apologize for that.
Now I understood how to use it !!
Thank you for your time!
Best regards,
Matheus Santos.