Prepare Ingredients: Clean and trim the fresh green beans. Chop the bacon into small pieces, dice the onion, and mince the garlic.
Sauté Bacon and Onion: Turn on the Instant Pot to the "Sauté" function. Add the chopped bacon and diced onion. Sauté until the bacon becomes crispy and the onion turns translucent. Stir occasionally.
Add Garlic: Stir in the minced garlic and sauté for about 30 seconds until fragrant.
Deglaze Pot: Pour in the chicken broth and use a wooden spoon to scrape any browned bits from the bottom of the Instant Pot.
Add Green Beans: Add the trimmed green beans to the Instant Pot, and season with salt, pepper, and red pepper flakes (if using). Stir to combine.
Pressure Cook: Close the Instant Pot lid, ensuring the vent is in the sealing position. Set the Instant Pot to "Manual" or "Pressure Cook" mode on high pressure for 3-4 minutes (3 minutes for crisp-tender beans, 4 minutes for softer beans).
Quick Release: Once the cooking time is up, perform a quick pressure release by turning the vent to "Venting" position. Be cautious of the hot steam.
Finish with Butter (Optional): If desired, stir in the butter to add extra richness to the dish.
Serve: Transfer the Instant Pot Southern Green Beans to a serving dish and enjoy them while they're hot.