To view your margin, go to the RMS Limits window.
RMS Limits is a window in Nest that provides a summary of your balance utilisation of limits with bifurcation and your positions on a real-time basis.
Press Ctrl + Shift + V or go to View Order/Trade Reports and select view RMS Limits
Under user option, select show all clients.
Click on your client code on the left and then refresh for results.