Heat oil in a medium size sauté pan over medium heat and sauté onions for 3 minutes. Add the mushroom, garlic, paprika and salt, and continue to sauté for 3 more minutes.
Add the cubed chicken and cook for 1 minute, stirring occasionally.
Add the sherry and water. Bring liquid to a boil then reduce to a simmer. Cook for 10 minutes until the liquid has reduced by half.
Turn heat off, add the sour cream and stir to combine.