Spicy Mexican chicken soup

Ingredients

• 1 tsp olive oil
• 1 small onion , diced
• 2 garlic cloves , minced
• 2 tsp tomato paste
• 1 tsp chili powder
• 900-mL carton no-salt chicken broth
• 1/4 tsp salt
• 2 skinless, boneless chicken breasts
• 2 cups canned tomatillos , chopped
• 2 cups frozen corn kernels
• 2 to 3 tbsp pickled jalapenos , finely diced
• 1 avocado , chopped
• 1/2 cup chopped cilantro