Cook bacon in a large pan until crisp, about 6 minutes. Drain on paper towels.
Heat oil in same pan over medium heat. Add onion; sauté until softened, 5 minutes. Add the potato and stock; simmer, partially covered, until potato is tender, about 20 minutes. Stir in corn. Simmer 5 minutes.
Place half the potato and corn with a little liquid in a food processor. Purée. Return to saucepan. Add capsicum, milk and salt. Cover and simmer for 10 minutes.
Finely chop the bacon. Stir into chowder with the chillies. Heat through and serve.