Lay the collard greens face down with the hard middle spines aligned. Use a sharp knife to cut through the stack, cutting out the spines. Discard the spines or save for another use.
Chop the collard greens into bite-sized pieces and wash in cold running water in a sieve or colander. Set aside to drain.
Chop the bacon into ½ inch pieces. Place in the bottom of the instant pot. Using the sauté setting cook the bacon until lightly golden brown. Add a teaspoon of olive oil if the bacon sticks to the bottom of the pot.
Remove the bacon with a slotted spoon and set aside in a small bowl.
Add the onion slices to the pot and cook in the bacon fat until just barely softened. Pause the instant pot.
Place the collard greens into the pot, pushing them down if needed.
Add the salt, pepper, and paprika to the pot. If using brown sugar, add it now. If using red pepper flakes or hot sauce add them now.
Pour in the chicken stock and vinegar. Using a big wooden spoon, lift the ingredients from the bottom to the top a few times to distribute the spices and wet the greens.
Secure the Instant Pot lid and set the pressure cooker to 16 minutes.
When the pressure cooker finishes cooking, allow the steam to escape completely before removing the lid! Safely Removing the Lid: Never attempt to remove the Instant Pot lid while the pot is pressurized. Wait until the float valve (pin) on the lid drops down to let you know that all of the pressure has been released. Read the manual and know how to safely use your cooker! Whether you allow the pressure to release naturally or you use the quick release method, only remove the lid when the pin is fully down. Remove the collard greens from the pot to a serving bowl and pour the pot liquor over the top.
Garnish with the cooked bacon bits.