Preheat the oven to 180C/350F. Line an 8 x 8-inch pan with parchment paper and grease it generously. Set aside.
In a large mixing bowl, combine your nuts with your crispy cereal. Pour the sugar free syrup over it and mix very well, until completely combined and all your nuts/cereal is coated in the syrup.
Transfer the granola bar mixture into the lined pan and using a rubber spatula, press down to ensure a uniform layer. Bake for 25 minutes.
Remove from the oven and allow to cool completely, before slicing into bars.
TO STORE: Granola bars are fragile and sticky, so should always be stored in the refrigerator. Keep them covered, and they will keep well for up to 4 weeks.TO FREEZE: Individually wrap bars in parchment paper and place them in a ziplock bag and store in the freezer for up to 6 months.