Heat the Instant Pot on saute mode for 3-5 minutes. Add oil to the inner pot. Sear the roast on both sides, then remove it from the pot and turn off saute mode.
Pour in the red wine, beef broth, and balsamic vinegar. Whisk the browned bits off the bottom of the pot. Let sit for 3 minutes for the alcohol to evaporate. Return the roast to the pot.
Lock the lid. Press the Pressure Cook button and set the time to 40 minutes. It will take 5-10 minutes for the pot to come up to pressure.
When the time is up, allow a 10 minute natural release. Add the potatoes and onions to the pot. Close the lid and set the time to 8 minutes. When the time is up, again allow a 10-minute natural release.
Remove the vegetables and roast from the pot. Allow the roast to rest for 5 minutes before slicing. During this time, turn on saute mode and cook down the broth until slightly thickened.
Serve the roast with the potatoes and onions, with sauce poured over the top.
Notes
Overcooking can lead to a dry and tough venison.
The size of your roast will also change the cook time. Mine was a 2 pound roast.