Preheat your oven to 250 degrees
In a small saucepan, melt butter until lightly bubbling. Add in maple syrup, chili crisp, and rosemary, and let simmer on low for a few minutes, letting all of those ingredients come together. Take off the heat and set aside
In a large bowl throw in the mixed nuts, and pour the maple chili crisp butter mixture over the top. Toss with some salt, taste, and then adjust if needed
Grease a large baking sheet with a little butter and spread the nuts in an even layer on the baking sheet
Pop in the oven for 45 minutes, stirring the nuts every 15 minutes
Take out at the 45-minute mark, let cool for a few minutes, and taste
Add a little more salt if needed, and enjoy!