Heat a tablespoon of olive oil in a large pot over medium heat until shimmering and fragrant.
Add the chopped onion and celery to the pot. Sauté, stirring occasionally, until they become translucent and slightly tender, about 5 minutes. The vegetables will give off a fragrant aroma and start to soften.
Add the minced garlic to the vegetables and cook for another minute, until fragrant and slightly golden.
Stir in the shredded chicken and sprinkle with smoked paprika, salt, and pepper. Mix well to coat the chicken evenly with the spices.
Pour in the chicken broth and bring the mixture to a gentle simmer. Once bubbling, reduce the heat and let it cook uncovered for about 20 minutes, skimming off any foam that rises to the surface.
Remove the pot from heat. Taste and adjust salt and pepper as needed, then stir in the chopped parsley and lemon juice for a fresh, bright finish.
Ladle the hot soup into bowls, ensuring each serving has plenty of shredded chicken and vegetables, and enjoy this cozy, keto-friendly dish.