Canada could very easily produce nuclear weapons, even at scale, if it wanted to. The U.S. would likely even help them in doing so if the government requested the assistance. As you say, it's one of the worlds main suppliers of uranium, already possesses highly advanced nuclear technology and facilities, and has the institutional know-how to be a nuclear power with low relative cost and minimal external interference. If even South Africa made and (supposedly, see below) tested a nuclear weapon way back in the 70's, many countries today and especially Canada could do so with little economic or technical difficulty.

https://en.wikipedia.org/wiki/Vela_incident