Press the Sauté button on the Instant Pot. When it is hot, add the bacon. Cook, stirring occasionally until crisp.
Meanwhile, wash and slice the leeks. Add the leeks to the pot once the bacon is crisp. Cook until soft.
Add garlic and cook for about a minute.
Stir in the chicken broth, mustard, salt, and pepper
Put the lid on. Set the steam release button to Seal. Press the Manual button and reduce (or increase) time to 7 minutes by pressing the - or + key.
Once the cooking cycle has finished, let the steam naturally release for 15 minutes. Manually release the remaining steam.
Open the lid. Stir in the coconut milk. Either use an immersion blender to blend the soup, or transfer it to a blender.
Transfer to serving bowls and garnish as desired.