Nudge provides a very robust way of removing extra junk from URLs as we see them. This means that, in almost all cases, no matter how a user visits your content, we will track their impression to the URL you'd expect.
Nudge's normalisation is almost transparent. The one thing to check, if you're worried about which URL to use, is https://ndg.io/installation/ - if you put your URL in here, we'll tell you which URL we track against.
In terms of the actual URL, we use the canonical URL if available, otherwise the page's URL. If you paste in the canonical URL, or a version of it inside the campaign edit screen, we'll normalise this behind the scenes and make sure all data that matches it, will match.
If you'd like to explore overriding URLs, this is also an option. Please contact support.