Put butter and sour cream on the potato, and slice up the avocado and eat it separately.
If you have a half left-over, which I know is a rarity for a lot of us, I have had success preserving the color of the left-over half by removing the pit and storing it cut side down on a plate and then into the fridge. As noted, the brown color does not affect flavor, but can be unappealing.
Mix the two with a little lime juice and salt, and have that on a nice taco or tortilla chips, and give the potato to the dog?
I love avocado and sour cream together, but the avocado needs to be soft and creamy.
Eat the avocado by itself.
Put the sour cream on the baked potato. Add some pepper and chives if they’re available. Eat the baked potato with its toppings.