Combine whisked egg whites, vanilla, sugar, brown sugar, salt, and cinnamon in a medium mixing bowl, whisking until well mixed.
Place mixed nuts in a large mixing bowl and pour the sugar mixture over them. Toss the nuts to ensure an even coating.
Grease the crock pot with nonstick spray and transfer the coated nuts into it.
Cook on low heat for 2-3 hours, stirring occasionally.
Line a large baking sheet with parchment paper. Spread the nuts in a single layer on the parchment paper. Allow them to cool and set.
Transfer the cooled nuts to an airtight container for storage, where they can be kept for up to one week.
Notes
Be sure to stir the nuts in the crockpot occasionally to ensure they cook and coat evenly.
When spreading the nuts on the parchment-lined baking sheet, try to separate them as much as possible to prevent clumping as they cool.
Make sure to whisk the egg whites until they are frothy and slightly thickened before adding the other ingredients. This will help create a better coating for the nuts.