Set Instant Pot to Saute. Add chopped bacon and cook until crisp. Transfer to a paper towel lined plate. Remove all but 1 tablespoon of grease. Add onion and cook about 5 minutes until softened, then add garlic, corn kernels, potatoes, and chipotle chilies and salt and pepper to taste. Add chicken broth and stir to combine. Cover and select Manual setting and cook on high pressure for 10 minutes. (It will take a few minutes for the Instant Pot to get to high pressure)

Use the quick release function to release the steam. Transfer half to a bowl and pulse with an emersion blender until chunky smooth, or place in blender to to the same. Return to the instant pot.

Set the Instant Pot to Saute and stir in milk and cheese. Cook until the cheese mils and the chowder starts to thicken, about 5 minutes. Add cilantro. Serve topped with green onions.