How fast does the NEXUS program get you across the border?

Not worth it, you'd have all the ag of bonding the load into Canada then lifting it again at the US border which would cost money and take plenty of time too.
Apparently it was common 30 years ago under different rules, and when the bridge collapsed in Nipigon a few years back there was a Thunder Bay to Sault ss or Detroit exemption for a few weeks while they repaired the bridge.

 

You need to make sure your product and count are 100% accurate, and make sure that your waybill is 100% against the product and count. You have to make sure your insurance, passport, and all that are up to date.

You need to fill out an A8B form (It is downloadable and printable), fill it out accurately, including your point of entry back into the US, you can't change your mind once it is filled out and accepted. Then you head to the border, have Canadian customs go through it, most likely inspect the trailer and truck, then stamp the form, and seal the trailer.

When you get to US POE, then they will make sure the seal is intact, they will go through your paperwork, they will stamp it if they accept it, and let you go on your way.

The last truck of mine that did this took an hour at the Canadian side and 20 minutes at the US POE - Detroit, but it was delivered right on Fort Street near the bridge in Detroit so it saved a lot of time.

Not sure if you need to be bonded, that's questionable and you can call Canadian customs about it.

 

I cross at Coutts and Sweetgrass all the time,most of the freight is going to Alaska,so we use the In-transit paperwork ,and the ACE form going back into America.
If you have the In Transit paperwork you have to stop at the Canada side on the way out and they will stamp the paperwork to release the bond.
I only use a passcard crossing the border ,it's only a few minutes wait.
But Coutts and Sweetgrass are probably not as busy as other crossings.