Sprinkle pork with 1/4 teaspoon salt and 1/8 teaspoon pepper.
Heat the oil in a large nonstick skillet over medium-high heat.
Add pork; saut 5 minutes on each side or until golden.
Remove pork from pan.
Add onion and mushrooms to pan; saut for 3 minutes. Carefully add whiskey to pan; cook for 1 minute or until liquid almost evaporates. Stir sour cream mixture into pan. Return pork to pan; spoon sauce over pork.
Wrap handle of skillet with foil. Cover and bake at 300 for 1 hour.