Preheat oven to 200 degrees. Place chicken in cling wrap and tenderise with a meat mallet. Mix flour, paprika and pepper in a large plastic bag, then add chicken breasts and shake until well coated. Melt butter with avocado oil in a pan over a medium heat. Cook chicken breasts through until golden (around 7-8 minutes), then place in an ovenproof dish and cover with foil to keep warm in the oven.
Soak the diced avocado pieces in lemon juice. Cook walnuts in the remaining butter and avocado oil in the pan, stir until crisp and brown. Drain pan and pour in chicken stock, bringing to boil over high heat and cook for 4-5 minutes. Stir in cream, bring to boil and cook for 2-3 minutes until slightly thickened. Take avocado pieces from the lemon juice and stir in sauce for 1 minute.
To serve, ladle sauce over chicken breasts, garnish with parsley, accompany with green vegetables and potatoes.