This recipe was tested in a 6-quart Instant Pot.
Instead of cubes or chunks, you can also cook rounds of sweet potato that are 1/2-inch thick using this cooking time and method.
If the sweet potato is not as soft as you'd like, then either set the lid back on the pot and let the potatoes steam longer in the residual heat or secure the lid and cook the potatoes for 1 to 3 more minutes.
These potatoes are soft enough to mash with a fork, but if you want really soft sweet potato cubes then increase the cooking time to 8 minutes.
Using a steamer basket yields the best results because it keeps the potatoes from getting waterlogged and soggy.