Add all the seasoning ingredients to a small pot and melt over medium heat.
Add the cereals, pretzels, and nuts to a large bowl. Pour the melted seasoning sauce over the chex mixture while stirring to evenly coat. Spread the mixture onto a large rimmed baking sheet. Bake for 60 minutes, stirring every 15 minutes until the mix has crisped up and become evenly golden. Let cool before serving or storing in an air-tight container.
In Canada, Chex cereals do not contain vitamin D3, but it has been brought to my attention that in the US Chex cereals do contain vitamin D3. D3 is usually made from lanolin and therefore is not vegan. So if you are in the US, look for a similar cereal that is vegan-friendly.