Heat a large lidded pan and add the chorizo. Fry for 2-3 minutes until just crisp. Remove the chorizo from the pan with a slotted spoon, leaving the oil.
Add the onion, garlic and chilli to the oil and cook gently for 3-5 minutes.
Add the thyme, chorizo, chickpeas and mixed beans to the pan and cook for 2 minutes. Stir in the chopped tomatoes and stock, and simmer, covered, for 10 minutes.
Remove the lid and simmer for a further 5 minutes, stirring occasionally, until the stew has thickened slightly. Ladle into mugs and serve.