In a small saucepan, fry your chorizo over a medium heat for a few minutes until the fat has rendered off and your chorizo is crisped up. Remove with a slotted spoon and set aside for later.
Tip your onions into the chorizo fat and cook over a low heat for 15-20 mins until they are totally soft and sweet. Top up with additional olive oil if necessary.
Tip your onions into your beaten egg along with your chorizo, crisps and seasoning. Stir to combine, then leave to sit for 5 mins until the crisps have softened and your flavours have had a chance to mingle.
Heat some oil in a small saute pan over a medium heat. Add your tortilla mix and cook for around 3 mins.
Place a plate on top of your pan and flip so that your tortilla is on the plate. Carefully slide back into the pan and cook the other side for 3 mins more.