Most goods are exempt from duties under NAFTA or not, if the items are dutiable normally using a NAFTA exemption form may get them through without duties.
Most goods that enter Canada from the USA are only subject to GST/HST and possibly PST, NAFTA won't change this in any way.

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915
- answering Trolls is voluntary, my policy is not to participate.