I hate to be the bearer of bad news, but Old Dutch is from Minnesota. The major portion of their production is done in Canada, and most of their customers are here, but their corporate head office is in the US.
I've noticed a lot of people on Bulk Barn's facebook page spamming them with requests for clear country of origin labels for every product. Hopefully they act on it.
My local Co-op website has them listed, if that helps.
*edit - Looked again and they're all cough drops, though. Maybe a different store will have different options.
Unfortunately American, but I really, really liked Vermont Chocolates' Skippers, always grabbed some when I drove to VT. Much higher quality than Mars M&M.
Hopefully some Canadian company can take their place.
You might also try looking for a local candy shop. Traditional candy is amazing! Stuff like toffee, fudge, peanut brittle, caramel popcorn, hand made chocolates, almond bark…
If you're willing to settle for. "Buy Commonwealth" as a fallback, British candy is generally not too hard to get ahold of, and bloody excellent (then again, I have an obvious bias there)
Both, but separately. When I was at Walmart last, I could find Belgian chocolate, British Wine Gums, etc. But I didn't really want to shop at Walmart, since their profits will still be funneled to the US.
So I went to my local Co-op. And everything there was basically Mars or Nestle or similar. Even the Co-op branded stuff was "imported by Co-op (Canada) under license" but wouldn't give me country of manufacture. Haribo and Storck were there from Germany, so it my objective was only to not-buy American, I could pull it off.
But the only things in the aisle that were provably Canadian were some of the chips and beef jerky.
Ended up with a bag of Haribo gummy bears.
Lots of other good advice in the comments, but I didn't see any of these brands in my Winnipeg Co-op. Will keep hunting :)
Ganong makes Chicken Bones, which are a cinnamon candy. They're mostly chocolate, though: Pal-o-Mine chocolate bars, Delecto Peanut Clusters, and they're introducing a new one they bought out from an American manufacture: Sixlets, which look like chocolate M&M's from the pictures and their website.
Prana makes a bunch of nut snacks like salted cashews and almonds.
If German is ok then definitely Haribo. Best Gummibears in the world!
For chocolate (and if you like mint) these are the best I have ever had and they are from Winnipeg: https://www.mordenschocolate.com/
Yeah, Morden's is amazing! I go directly to their store here in Winnipeg sometimes. But they are super expensive for something like D&D snacks that will be consumed in large quantities over several hours :)
If you have a really sweet tooth, there is the Canadian Candy Company, in Cobourg, Ontario. The only problem is that unless you go to their outlet store beside the factory, you have to buy candy by the pallet (looks like about 700kg).
Being in this part of Ontario I love Rheo Thompson mint smoothies. When I first moved here I literally thought "mint smoothie" meant some sort of tacky mint drink mix then I finally found some on sale for charity at my local Pharmasave and was converted :)