Turn on your instant pot to saute and add the oil.
Add bacon (about 4 or 5 pieces seem to fit) and cook around 2 minutes per side or until crispy. This might take 2 rounds to get all your bacon.
Remove back and set aside to let it further crisp. Crumble it (or cut it up with kitchen scissors) and return it to the pan. Remove excess bacon grease if there's a lot.
Add onion and let it cook until it becomes tender, this takes around 4 minutes.
Then add the garlic and stir well so it doesn't overcook.
Add in the collard greens and, using tongs if you have them, get all of the greens into the onion, garlic, and oil mixture so they begin to wilt.
Once all the collards are coated, add the chicken stock, brown sugar, salt, pepper, and red pepper flakes if you're using them.
Put the lid on the instant pot to sealing, then turn it onto Manual for 10 minutes.
Let it cook for 10 minutes, then turn it off. You can either vent it yourself automatically or let it self-vent.