Hit the saute button and add the ground beef and onion to the pressure cooker pot.
Cook until no longer pink, breaking up and stirring as you go.
Remove the pot, drain the grease, and return the pot to the Instant Pot.
Add the broth, water, and vegetables.
Close the pot and set the cook time for 10 minutes.
Let the pressure release naturally for five to ten minutes, then release remaining pressure.
While the pressure releases, melt the butter in a sauce pan on the stove.
Whisk in the flour and cook for one minute.
Whisk in the milk.
Add the Velveeta and stir until the cheese is melted and the sauce is thickened.
Add the cheese sauce to the pressure cooker pot and stir to combine.
Season with salt and pepper.