For the pressure cooker, add the Brussels sprouts, water and liquid smoke to your Instant Pot and mix well. Put the lid on and close the pressure valve. Cook on high pressure for 2 minutes. (Note: If you have very large Brussels sprouts, you may need to double the cooking time.)
Once the cooking time is up, carefully move the pressure release valve to release the pressure manually.
For the sauté, switch to the sauté function and add in the pecans and maple syrup and reduce the liquid as you finish cooking the sprouts. Remove from the heat once tender and add salt to taste.
Notes
To save time, you can chop the pecans while the Brussels sprouts are in the pressure cooker - it takes a few minutes for the pot to come to pressure, plus two minutes for them to cook, and I had plenty of times to roughly chop some pecans in that time. I accounted for the time it takes the Instant Pot to come to pressure into account when calculating the total cooking time. This can vary, so the cooking time is an estimate.