Grind oatmeal in a blender.
Add all ingredients and mix. Add 10g of chocolate.
Add nuts, then microwave for 1 minute, stop for 3 seconds, and run for another 15 seconds (if chocolate remains melted, let it cook with residual heat for 5 or 10 seconds).
For air fryer: 10 minutes at 170°C, then 5 minutes at 150°C.