Hardware Latency Compensation

As scook says, the external insert plugin is the, or at least probably the simplest, way to go.

You don't need to use the plugin, you can do the job simply by using two tracks, one playin the recorded audio out to interface and the other recirding the return. If you can get low enough round trip latency you can monitor via track echo using either method. Otherwise monitor the loopback directly through the interface.

Without using the plugin, you can line up the original and re-recorded tracks simply by zooming right in and dragging the audio in the processed track until a prominent transient in it (big transients are the easiest thing to spot) lines up with its equivalent in the original unprocessed track. The best way I find is to put a kick drum or hi-hat symbol at the beginning or end of the original track, record it to the new track along with the rest of the audio, then into use it as a guide to nudging the new recording, after which delete the drum/hat sample from both tracks.

Sometimes you'll need to nudge the new recording backwards or forwards a big even if the external insert plugin has been used, some hardware processors, especially if they are digitsl in any way, have latency of their own which can vary slightly as they do their thing.