Chicken and pumpkin tacos

Ingredients

• 1 tablespoon vegetable or olive oil
• 1 medium brown onion, finely chopped
• 500 gram pumpkin, cut into 2cm pieces
• 1/3 cup sunflower seeds
• 550 gram chicken mince
• 35 gram packet taco seasoning mix
• 125 gram can creamed corn
• 12 taco shells
• 3 iceberg lettuce leaves, shredded
• 1 large avocado, finely chopped
• 1/2 cup sour cream