Turn the instant pot setting to saute and add butter. Let the butter heat for 1 minute. Add the asparagus tips reserved for garnish and saute for 2 minutes then remove and set aside.
Add the diced onion and saute for 3-5 minutes or until beginning to soften and become translucent. Add minced garlic and saute for another 30-60 seconds.
Carefully pour in the white wine. Gently scrape up any browned bits from the bottom of the pot and cook for another minute. Add the asparagus stock, diced potatoes and diced asparagus stems. Season with another pinch of salt and pepper.
Secure the lid and make sure the steam release is closed. Turn the instant pot setting to HIGH pressure and set the timer for 6 minutes. When done, let the pressure release naturally for 10 minutes, then press the button to quick release.
Stir in the coconut milk and use an immersion blender to puree until smooth, or blend in batches using a high speed blender. Squeeze with lemon juice and top with asparagus tips before serving.