Combine oil and garlic in a bowl. Add fish and toss to coat. Cover and refrigerate for 30 minutes to marinate.
Preheat barbecue on high. Thread a cube of fish, a slice of chilli and a slice of chorizo onto a bamboo skewer. Repeat with remaining ingredients and brush with garlic marinade. Cook on grill plate for 2 minutes each side, until golden and cooked through. Serve.