Set a 6-quart or larger Instant Pot to sauté. Once hot, add the oil, onions, garlic and crushed red pepper flakes. Cook until softened, about 3 minutes. Add the ham hocks and sauté for another minute. Turn off the machine and stir in the black eyed peas, collard greens, salt, pepper, chicken stock, bay leaves, thyme, and liquid smoke.
Lock the lid in place, making sure the valve is set to seal, and pressure cook on high for 25 minutes. Allow the machine to natural release for 10 minutes before manually releasing any residual steam.
Carefully open the lid and stir in the vinegar and hot sauce. Give it a taste and adjust seasoning accordingly. Discard the ham hock bones and serve immediately.