In A Saucepan, Saute Celery In Butter Until Tender. Add Bouillon, Stirring Until Dissolved. Stir In The Flour, Salt And Poultry Seasoning Until Blended. Gradually Add Milk, Stirring Until Smooth. Bring To A Boil Over Medium Heat; Cook And Stir For 2 Minutes Or Until Thickened. Add The Chicken, Pimientos, Lemon Juice And Half Of The Pecans; Cook Until Heated Through. Serve Over The Rice. Sprinkle With Remaining Pecans.